{"id":24093,"date":"2025-10-10T08:21:09","date_gmt":"2025-10-10T08:21:09","guid":{"rendered":"https:\/\/1-grid.com\/knowledge\/blocked-via-mailchannels-due-to-spam\/"},"modified":"2025-11-06T12:04:31","modified_gmt":"2025-11-06T12:04:31","slug":"blocked-via-mailchannels-due-to-spam","status":"publish","type":"ht_kb","link":"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/","title":{"rendered":"Resolving a MailChannels Spam Block &#8220;550 5.7.1&#8221; Error"},"content":{"rendered":"\n<p>The \u201c550 5.7.1 [CS] Message blocked Spam\u201d error with MailChannels can be frustrating; however, it doesn\u2019t mean your domain is permanently blocked. By applying authentication, cleaning mailing lists, and following safe sending practices, resolving a MailChannels spam message block can be quick and <a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-avoid-mailchannels-blocks\/\"><strong>prevent future blocks<\/strong><\/a>.&nbsp;<\/p>\n\n\n\n<p>This guide will help you understand this error and how to prevent it from happening.&nbsp;<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1600\" height=\"600\" src=\"https:\/\/1grid.co.za\/knowledge\/wp-content\/uploads\/2022\/02\/1-grid-Images-for-KB-Articles-1000-x-600-px-46.png\" alt=\"\" class=\"wp-image-33789\"\/><\/figure>\n<\/div>\n\n\n<div class=\"wp-block-ht-block-toc is-style-rounded htoc htoc--position-wide toc-list-style-plain\" data-htoc-state=\"expanded\"><span class=\"htoc__title\"><span class=\"ht_toc_title\">Table of Contents<\/span><span class=\"htoc__toggle\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"16\" height=\"16\"><g fill=\"#444\"><path d=\"M15 7H1c-.6 0-1 .4-1 1s.4 1 1 1h14c.6 0 1-.4 1-1s-.4-1-1-1z\"><\/path><path d=\"M15 1H1c-.6 0-1 .4-1 1s.4 1 1 1h14c.6 0 1-.4 1-1s-.4-1-1-1zM15 13H1c-.6 0-1 .4-1 1s.4 1 1 1h14c.6 0 1-.4 1-1s-.4-1-1-1z\"><\/path><\/g><\/svg><\/span><\/span><div class=\"htoc__itemswrap\"><ul class=\"ht_toc_list\"><li class=\"\"><a href=\"#htoc-\">What Does This Error Mean?&nbsp;&nbsp;&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-1\">Why MailChannels Blocks Emails&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-1111\">How to Fix the Error&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-1111111111\">Tips to Reduce Spam Flags<\/a><ul class=\"ht_toc_child_list\"><li class=\"\"><a href=\"#htoc-111111111111\">1. Maintaining Mail Reputation&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-1111111111111\">2. Scanning Devices with Antivirus Software&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-111111111111111111\">3. Consider Changing Your Email Password&nbsp;<\/a><\/li><\/ul><\/li><li class=\"\"><a href=\"#htoc-1111111111111111111\">How to Prevent Future Blocks&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-1111111111111111111111\">When to Contact 1-grid Support&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-11111111111111111111111111\">FAQs&nbsp;&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-11111111111111111111111111111111\">Additional Resources&nbsp;<\/a><\/li><\/ul><\/div><\/div>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-\"><strong>What Does This Error Mean?&nbsp;&nbsp;&nbsp;<\/strong><\/h2>\n\n\n\n<p>If you see the \u201c<strong>550 5.7.1 [CS] Message blocked Spam<\/strong>\u201d error, MailChannels detected something in your email that looked like spam. This could be your content, your list quality, or even a compromised account.&nbsp;&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-1\"><strong>Why MailChannels Blocks Emails&nbsp;<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-11\"><a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-resolve-mailchannels-error-550-too-many-invalid-recipients\/\"><strong>Sending to invalid or inactive addresses<\/strong><\/a>.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-messages-with-spam-like-wording-attachments-or-suspicious-links\">Messages with spam-like wording, attachments, or suspicious links.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-accounts-compromised-by-malware-or-weak-passwords\">Accounts compromised by malware or weak passwords.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-missing-or-misconfigured-spf-dkim-or-dmarc\">Missing or misconfigured <a href=\"https:\/\/1grid.co.za\/knowledge\/cpanel-how-to-setup-an-spf-record\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>SPF<\/strong><\/a>, <a href=\"https:\/\/1grid.co.za\/knowledge\/cpanel-how-to-generate-a-new-dkim-record\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>DKIM<\/strong><\/a>, or <a href=\"https:\/\/1grid.co.za\/knowledge\/cpanel-how-to-add-dmarc-record\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>DMARC<\/strong><\/a>.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-111\">High complaint rates from recipients.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-1111\"><strong>How to Fix the Error&nbsp;<\/strong><\/h2>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>1. Check the Content<\/strong><\/summary>\n<p id=\"htoc-11111\">Remove <a href=\"https:\/\/www.activecampaign.com\/blog\/spam-words\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>spammy phrases<\/strong><\/a>, <a href=\"https:\/\/easydmarc.com\/tools\/phishing-url\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>suspicious links<\/strong><\/a>, or large attachments.&nbsp;<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>2. Authenticate Your Domain<\/strong><\/summary>\n<p id=\"htoc-111111\">Add <a href=\"https:\/\/1grid.co.za\/knowledge\/cpanel-how-to-setup-an-spf-record\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>SPF<\/strong><\/a>, <a href=\"https:\/\/1grid.co.za\/knowledge\/cpanel-how-to-generate-a-new-dkim-record\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>DKIM<\/strong><\/a>, and <a href=\"https:\/\/1grid.co.za\/knowledge\/cpanel-how-to-add-dmarc-record\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>DMARC<\/strong><\/a> records to validate your email.&nbsp;<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>3. Secure Your Account<\/strong><\/summary>\n<p id=\"htoc-1111111\"><a href=\"https:\/\/1grid.co.za\/knowledge\/?s=change+password&amp;ht-kb-search=1&amp;lang=\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Change your password<\/strong><\/a>, update your operating system, and run antivirus scans.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>4. Clean Your Mailing List<\/strong><\/summary>\n<p id=\"htoc-11111111\">Remove <strong><a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-resolve-mailchannels-error-550-too-many-invalid-recipients\/\">invalid addresses<\/a> <\/strong>or unengaged contacts.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>5. Retry Sending<\/strong><\/summary>\n<p id=\"htoc-111111111\">Once fixes are applied, retry the message.<\/p>\n<\/details>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-1111111111\"><strong>Tips to Reduce Spam Flags<\/strong><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"htoc-111111111111\"><strong>1. Maintaining Mail Reputation<\/strong>&nbsp;<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-11111111111\">Don\u2019t write emails <strong>without a subject line<\/strong>.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-don-t-write-subject-lines-all-in-caps\">Don\u2019t write <strong>subject lines in ALL IN CAPS<\/strong>.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-don-t-plea-with-people-to-open-me\">Don\u2019t <strong>plead <\/strong>with people to <strong>\u201cOpen Me!\u201d<\/strong>&nbsp;<\/li>\n\n\n\n<li id=\"htoc-don-t-deceive-readers-with-a-false-promise\">Don\u2019t<strong> deceive <\/strong>readers <strong>with a false promise<\/strong>.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-don-t-give-away-everything-in-your-subject-line-do-not-make-your-subject-line-too-long\">Don\u2019t <strong>give away everything in your subject line<\/strong> (Do not <strong>make your subject line too long<\/strong>).&nbsp;<\/li>\n\n\n\n<li id=\"htoc-don-t-use-one-word-like-hi-as-your-subject-line\">Don\u2019t <strong>use one word<\/strong> like \u201cHi!\u201d as your subject line.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-skip-the-punctuation\">Skip the <strong>punctuation!!!&nbsp;<\/strong><\/li>\n\n\n\n<li id=\"htoc-don-t-add-re-to-your-subject-line-to-deceive-readers\">Don\u2019t <strong>add Re:<\/strong> to your subject line to deceive readers.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-1111111111111111111111111\">Avoid <strong>using blacklisted URLs<\/strong> or <strong>suspicious\/bad attachments<\/strong> in the mails.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"htoc-1111111111111\"><strong>2. Scanning Devices with Antivirus Software<\/strong>&nbsp;<\/h3>\n\n\n\n<p><strong>Recommended Antivirus Solutions (Paid)&nbsp;<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-11111111111111\"><a href=\"https:\/\/www.malwarebytes.com\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Malwarebytes<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<\/li>\n\n\n\n<li id=\"htoc-bitdefender\"><a href=\"https:\/\/www.google.com\/aclk?sa=L&amp;ai=DChsSEwiVh_nav4CQAxVZpFAGHcXZMPwYACICCAEQABoCZGc&amp;co=1&amp;ase=2&amp;gclid=CjwKCAjw_-3GBhAYEiwAjh9fUH2hjysxv_cESi6rDQQ-8novr8Mucms52MWal4IhADrl9xzmKKgO8BoCRSIQAvD_BwE&amp;cid=CAASNuRoMAxQBevWZ6PSen54rPuXFmAc_JaDX1Yiy7LnR1C8P4o-7qbDRWruATxH7tI5w8NvmgJ7mg&amp;cce=2&amp;category=acrcp_v1_32&amp;sig=AOD64_3Pwe-J6aFGq1CHpAoyu37BmTKAig&amp;q&amp;nis=4&amp;adurl&amp;ved=2ahUKEwiP1vPav4CQAxVlV0EAHXggDrUQ0Qx6BAgaEAE\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Bitdefender<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<\/li>\n\n\n\n<li id=\"htoc-norton-antivirus\"><a href=\"https:\/\/us.norton.com\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Norton Antivirus<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<\/li>\n\n\n\n<li id=\"htoc-mcafee\"><a href=\"https:\/\/www.mcafee.com\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>McAfee<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<\/li>\n\n\n\n<li id=\"htoc-111111111111111\"><a href=\"https:\/\/www.kaspersky.co.za\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Kaspersky<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<\/li>\n<\/ul>\n\n\n\n<p><strong>Free Antivirus Solutions&nbsp;<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-1111111111111111\"><a href=\"https:\/\/www.avg.com\/en-us\/free-antivirus-download\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>AVG Free<\/strong><\/a> (For PC)&nbsp;&nbsp;<\/li>\n\n\n\n<li id=\"htoc-avg-free-for-all-devices\"><a href=\"https:\/\/www.avg.com\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>AVG Free<\/strong><\/a><strong> <\/strong>(For All Devices)&nbsp;&nbsp;<\/li>\n\n\n\n<li id=\"htoc-microsoft-defender-built-into-windows\"><a href=\"https:\/\/apps.microsoft.com\/detail\/9p6pmztm93lr?hl=en-US&amp;gl=US\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Microsoft Defender<\/strong><\/a> (built into Windows)&nbsp;&nbsp;<\/li>\n\n\n\n<li id=\"htoc-totalav-free\"><a href=\"https:\/\/www.totalav.com\/free-antivirus-software-2\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>TotalAV Free<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<\/li>\n\n\n\n<li id=\"htoc-11111111111111111\"><a href=\"http:\/\/www.lavasoft.com\/home.php\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Lavasoft<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<\/li>\n<\/ul>\n\n\n\n<p><strong>TIP: <\/strong>Choose a solution that provides real-time scanning, phishing protection, and suspicious website alerts.&nbsp;<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"htoc-111111111111111111\"><strong>3. Consider Changing Your Email Password<\/strong>&nbsp;<\/h3>\n\n\n\n<p>Sometimes, a<strong> <a href=\"https:\/\/1grid.co.za\/knowledge\/?s=change+password&amp;ht-kb-search=1&amp;lang=\" target=\"_blank\" rel=\"noreferrer noopener\">good practice is to keep your email passwords refreshed<\/a><\/strong>. This, however, means ensuring that you make changes across devices, and not just for Webmail.&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-1111111111111111111\"><strong>How to Prevent Future Blocks&nbsp;<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-11111111111111111111\">Use <strong><a href=\"https:\/\/customer.io\/learn\/deliverability\/double-opt-in-best-practices\">double opt-in<\/a><\/strong> to confirm subscribers.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-keep-lists-updated-and-remove-invalid-recipients-regularly\">Keep lists updated and remove invalid recipients regularly.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-write-clear-relevant-subject-lines-avoid-free-or-all-caps\">Write clear, relevant subject lines (avoid \u201cFREE $$$\u201d or all caps).&nbsp;<\/li>\n\n\n\n<li id=\"htoc-don-t-send-bulk-messages-without-warming-up-gradually\">Don\u2019t send bulk messages without warming up gradually.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-111111111111111111111\">Regularly <strong><a href=\"https:\/\/www.google.com\/aclk?sa=L&amp;ai=DChsSEwiXieWvlpmQAxXqnFAGHfp8NuAYACICCAEQABoCZGc&amp;co=1&amp;ase=2&amp;gclid=Cj0KCQjw3aLHBhDTARIsAIRij58erfPTynu8xx68BiyQ7bZDU8HP9C4erOZ5HmkqpBBN1V4Wkgsm_i4aAsUmEALw_wcB&amp;cid=CAASNuRoMBhvkARh-kmsnBSUnLDjmM3Icv27xrvwCi_7-xsoHdsFxUYewkPy4aIbjdlEkqM0jGpnxw&amp;cce=2&amp;category=acrcp_v1_32&amp;sig=AOD64_2Kq_P_pmJ42AMcJzZaLSJdwxHyQw&amp;q&amp;nis=4&amp;adurl&amp;ved=2ahUKEwiEjOCvlpmQAxUAW0EAHcx5GiAQ0Qx6BAgYEAE\">monitor DMARC<\/a> <\/strong>and MailChannels reports.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-1111111111111111111111\"><strong>When to Contact 1-grid Support&nbsp;<\/strong><\/h2>\n\n\n\n<p>If you\u2019ve followed these steps and still experience MailChannels blocks, contact our Support Team.&nbsp;&nbsp;<\/p>\n\n\n\n<p>Provide the following (with screenshots, where possible):&nbsp;<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-11111111111111111111111\">The full bounce-back message.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-steps-you-ve-already-tried\">Steps you\u2019ve already tried.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-111111111111111111111111\">Details of your SPF, DKIM, and DMARC setup.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-11111111111111111111111111\"><strong>FAQs&nbsp;&nbsp;<\/strong><\/h2>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Is my domain blacklisted if I see this error?<\/strong><\/summary>\n<p id=\"htoc-111111111111111111111111111\">Not necessarily. This error is usually temporary and can be resolved by fixing content or authentication.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Can MailChannels blocks happen even with small email volumes?<\/strong><\/summary>\n<p id=\"htoc-1111111111111111111111111111\">Yes, if messages look suspicious or are sent to invalid recipients.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Will SPF, DKIM, and DMARC prevent all blocks?<\/strong><\/summary>\n<p id=\"htoc-11111111111111111111111111111\">They prevent many, but sending practices also play a big role.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>How fast can I resume sending after fixing issues?<\/strong><\/summary>\n<p id=\"htoc-111111111111111111111111111111\">In most cases, once problems are resolved, sending resumes automatically.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Can 1-grid unblock me if this was a false positive?<\/strong><\/summary>\n<p id=\"htoc-1111111111111111111111111111111\">Yes, 1-grid can escalate the issue to MailChannels for review.<\/p>\n<\/details>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-11111111111111111111111111111111\"><strong>Additional Resources&nbsp;<\/strong><\/h2>\n\n\n\n<p><a href=\"https:\/\/1grid.co.za\/knowledge\/mailchannels-errors-codes\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>MailChannels Error Codes and How to Fix Them<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-resolve-mailchannels-error-550-too-many-invalid-recipients\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>How to Resolve MailChannels Error 550 \u201cToo many invalid recipients\u201d<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/?s=mailchannels&amp;ht-kb-search=1&amp;lang=\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>MailChannels FAQs<\/strong><\/a><br><a href=\"https:\/\/1grid.co.za\/knowledge\/?s=change+password&amp;ht-kb-search=1&amp;lang=\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Updating My Password FAQs<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/top-10-common-email-issues-and-how-to-resolve-them\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Top 10 Common Email Issues and How to Resolve Them<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/setting-up-email-in-outlook-via-windows-control-panel\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Setting Up Email in Outlook via Windows Control Panel<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-set-up-email-on-android-for-your-1grid-email-accounts\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>How to Set Up Email on Android for Your 1-grid Email Accounts<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/settings-to-configure-your-1grid-email-accounts-across-devices\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Settings to Configure Your 1-grid Email Accounts Across Devices<\/strong><\/a><strong>&nbsp;&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/resolving-email-error-messages-when-sending-to-gmail-accounts\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Resolving Email Error Messages When Sending to Gmail Accounts<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/what-is-ip-blacklisting\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>What is IP Blacklisting?<\/strong><\/a>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-check-if-my-ip-is-blacklisted\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>How Do I Check if My IP is Blacklisted?<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/spamtitan-how-to-blacklist-an-email-address-or-domain\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>SpamTitan: How to Blacklist an Email Address or Domain<\/strong><\/a>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/what-is-email-spoofing\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>What Is Email Spoofing? How It Works and How to Protect Yourself&nbsp;<\/strong><\/a>&nbsp;&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-spot-a-scam-email\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>How to Spot a Scam Email<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/?s=email+headers&amp;ht-kb-search=1&amp;lang=\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Email Headers FAQs<\/strong><\/a>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/?s=email&amp;ht-kb-search=1&amp;lang=\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Email FAQs<\/strong><\/a>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-enable-dkim-and-spf-on-your-mail-domain\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>How to Enable DKIM and SPF on Your Mail Domain<\/strong><\/a><strong>&nbsp;<\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/why-ssl-the-purpose-of-using-ssl-certificates\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Why SSL? The Purpose of Using SSL Certificates<\/strong><\/a><strong> <\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/what-is-a-domain-name-server-dns\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>What is a Domain Name Server (DNS)?<\/strong><\/a>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-update-your-domains-nameservers-at-1-grid\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>How to Update Your Domain\u2019s Nameservers at 1-grid<\/strong><\/a><strong>&nbsp; <\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/?s=spamtitan&amp;ht-kb-search=1&amp;lang=\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>SpamTitan FAQs<\/strong><\/a>&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-111111111111111111111111111111111\"><strong>Need Additional Support?&nbsp;<\/strong><\/h2>\n\n\n\n<p><strong>We&#8217;re Here to <\/strong><a href=\"https:\/\/1grid.co.za\/knowledge\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Help<\/strong><\/a><strong>:<\/strong>&nbsp;<\/p>\n\n\n\n<p>Preventing emails from being blocked by MailChannels as a spam block doesn\u2019t have to feel technical with this easy-to-reference guide. Stuck? Contact our Support Team for clarity and guidance (<a href=\"https:\/\/1grid.co.za\/contact-us\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>https:\/\/1grid.co.za\/contact-us\/<\/strong><\/a>). We&#8217;re ready to see how we can help!&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The \u201c550 5.7.1 [CS] Message blocked Spam\u201d error with MailChannels can be frustrating; however, it doesn\u2019t mean your domain is permanently blocked. By applying authentication, cleaning mailing lists, and following safe sending practices, resolving a MailChannels spam message block can be quick and prevent future blocks.&nbsp; This guide will help&#8230;<\/p>\n","protected":false},"author":21,"comment_status":"closed","ping_status":"closed","template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"ht-kb-category":[1173,1194],"ht-kb-tag":[141,184,325,344,594,598,935,1498,1094],"class_list":["post-24093","ht_kb","type-ht_kb","status-publish","format-standard","hentry","ht_kb_category-email","ht_kb_category-email-troubleshooting","ht_kb_tag-blocked","ht_kb_tag-channel","ht_kb_tag-due","ht_kb_tag-email-hosting","ht_kb_tag-mail","ht_kb_tag-mailchannels","ht_kb_tag-spam","ht_kb_tag-spam-block","ht_kb_tag-via"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.0 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Resolving a MailChannels Spam Block &quot;550 5.7.1&quot; Error - 1-grid Knowledge Base<\/title>\n<meta name=\"description\" content=\"Learn why a MailChannels spam block error 550 5.7.1. happens, how to resolve it, and best practices to prevent future email delivery issues.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Resolving a MailChannels Spam Block &quot;550 5.7.1&quot; Error - 1-grid Knowledge Base\" \/>\n<meta property=\"og:description\" content=\"Learn why a MailChannels spam block error 550 5.7.1. happens, how to resolve it, and best practices to prevent future email delivery issues.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/\" \/>\n<meta property=\"og:site_name\" content=\"1-grid Knowledge Base\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/1grid.co.za\/\" \/>\n<meta property=\"article:modified_time\" content=\"2025-11-06T12:04:31+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/1grid.co.za\/knowledge\/wp-content\/uploads\/2022\/02\/1-grid-Images-for-KB-Articles-1000-x-600-px-46.png\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:site\" content=\"@1grid_hosting\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"4 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/\",\"url\":\"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/\",\"name\":\"Resolving a MailChannels Spam Block \\\"550 5.7.1\\\" Error - 1-grid Knowledge Base\",\"isPartOf\":{\"@id\":\"https:\/\/1grid.co.za\/knowledge\/#website\"},\"datePublished\":\"2025-10-10T08:21:09+00:00\",\"dateModified\":\"2025-11-06T12:04:31+00:00\",\"description\":\"Learn why a MailChannels spam block error 550 5.7.1. happens, how to resolve it, and best practices to prevent future email delivery issues.\",\"breadcrumb\":{\"@id\":\"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/1grid.co.za\/knowledge\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Resolving a MailChannels Spam Block &#8220;550 5.7.1&#8221; Error\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/1grid.co.za\/knowledge\/#website\",\"url\":\"https:\/\/1grid.co.za\/knowledge\/\",\"name\":\"1-Grid Domain Hosting Knowledge Base\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\/\/1grid.co.za\/knowledge\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/1grid.co.za\/knowledge\/?s={search_term_string}\"},\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/1grid.co.za\/knowledge\/#organization\",\"name\":\"1-Grid Domain Hosting Knowledge Base\",\"url\":\"https:\/\/1grid.co.za\/knowledge\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/1grid.co.za\/knowledge\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/1grid.co.za\/knowledge\/wp-content\/uploads\/2023\/01\/1-grid-logo-color.svg\",\"contentUrl\":\"https:\/\/1grid.co.za\/knowledge\/wp-content\/uploads\/2023\/01\/1-grid-logo-color.svg\",\"width\":100,\"height\":100,\"caption\":\"1-Grid Domain Hosting Knowledge Base\"},\"image\":{\"@id\":\"https:\/\/1grid.co.za\/knowledge\/#\/schema\/logo\/image\/\"},\"sameAs\":[\"https:\/\/www.facebook.com\/1grid.co.za\/\",\"https:\/\/twitter.com\/1grid_hosting\",\"https:\/\/www.instagram.com\/1grid_hosting\/\",\"https:\/\/za.linkedin.com\/company\/1-grid\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Resolving a MailChannels Spam Block \"550 5.7.1\" Error - 1-grid Knowledge Base","description":"Learn why a MailChannels spam block error 550 5.7.1. happens, how to resolve it, and best practices to prevent future email delivery issues.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/","og_locale":"en_US","og_type":"article","og_title":"Resolving a MailChannels Spam Block \"550 5.7.1\" Error - 1-grid Knowledge Base","og_description":"Learn why a MailChannels spam block error 550 5.7.1. happens, how to resolve it, and best practices to prevent future email delivery issues.","og_url":"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/","og_site_name":"1-grid Knowledge Base","article_publisher":"https:\/\/www.facebook.com\/1grid.co.za\/","article_modified_time":"2025-11-06T12:04:31+00:00","og_image":[{"url":"https:\/\/1grid.co.za\/knowledge\/wp-content\/uploads\/2022\/02\/1-grid-Images-for-KB-Articles-1000-x-600-px-46.png"}],"twitter_card":"summary_large_image","twitter_site":"@1grid_hosting","twitter_misc":{"Est. reading time":"4 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/","url":"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/","name":"Resolving a MailChannels Spam Block \"550 5.7.1\" Error - 1-grid Knowledge Base","isPartOf":{"@id":"https:\/\/1grid.co.za\/knowledge\/#website"},"datePublished":"2025-10-10T08:21:09+00:00","dateModified":"2025-11-06T12:04:31+00:00","description":"Learn why a MailChannels spam block error 550 5.7.1. happens, how to resolve it, and best practices to prevent future email delivery issues.","breadcrumb":{"@id":"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/1grid.co.za\/knowledge\/"},{"@type":"ListItem","position":2,"name":"Resolving a MailChannels Spam Block &#8220;550 5.7.1&#8221; Error"}]},{"@type":"WebSite","@id":"https:\/\/1grid.co.za\/knowledge\/#website","url":"https:\/\/1grid.co.za\/knowledge\/","name":"1-Grid Domain Hosting Knowledge Base","description":"","publisher":{"@id":"https:\/\/1grid.co.za\/knowledge\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/1grid.co.za\/knowledge\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/1grid.co.za\/knowledge\/#organization","name":"1-Grid Domain Hosting Knowledge Base","url":"https:\/\/1grid.co.za\/knowledge\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/1grid.co.za\/knowledge\/#\/schema\/logo\/image\/","url":"https:\/\/1grid.co.za\/knowledge\/wp-content\/uploads\/2023\/01\/1-grid-logo-color.svg","contentUrl":"https:\/\/1grid.co.za\/knowledge\/wp-content\/uploads\/2023\/01\/1-grid-logo-color.svg","width":100,"height":100,"caption":"1-Grid Domain Hosting Knowledge Base"},"image":{"@id":"https:\/\/1grid.co.za\/knowledge\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.facebook.com\/1grid.co.za\/","https:\/\/twitter.com\/1grid_hosting","https:\/\/www.instagram.com\/1grid_hosting\/","https:\/\/za.linkedin.com\/company\/1-grid"]}]}},"_links":{"self":[{"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/ht-kb\/24093","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/ht-kb"}],"about":[{"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/types\/ht_kb"}],"author":[{"embeddable":true,"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/users\/21"}],"replies":[{"embeddable":true,"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/comments?post=24093"}],"version-history":[{"count":5,"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/ht-kb\/24093\/revisions"}],"predecessor-version":[{"id":34064,"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/ht-kb\/24093\/revisions\/34064"}],"wp:attachment":[{"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/media?parent=24093"}],"wp:term":[{"taxonomy":"ht_kb_category","embeddable":true,"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/ht-kb-category?post=24093"},{"taxonomy":"ht_kb_tag","embeddable":true,"href":"https:\/\/1grid.co.za\/knowledge\/wp-json\/wp\/v2\/ht-kb-tag?post=24093"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}