{"id":24030,"date":"2025-10-07T11:33:49","date_gmt":"2025-10-07T11:33:49","guid":{"rendered":"https:\/\/1-grid.com\/knowledge\/email-error-messages-what-do-they-mean\/"},"modified":"2026-03-10T12:24:17","modified_gmt":"2026-03-10T12:24:17","slug":"email-error-messages-what-do-they-mean","status":"publish","type":"ht_kb","link":"https:\/\/1grid.co.za\/knowledge\/email-error-messages-what-do-they-mean\/","title":{"rendered":"Email Error Messages: What Do They Mean and How to Fix Them"},"content":{"rendered":"\n<p>Every mail server and client is unique, and so are their error responses. When you send or receive email, errors may occur, and often the message you see contains the clue you need to fix it. Because we know it\u2019s not always easy to decipher what they\u2019re trying to tell you, we\u2019ve collected a list of the most common email error messages and their variations. <br><br>This guide will help you with how to read those error messages, interpret them, and resolve them. &nbsp;&nbsp;<\/p>\n\n\n\n<figure class=\"wp-block-image 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-39.png\" alt=\"\" class=\"wp-image-33767\"\/><\/figure>\n\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-\">How Email Error Messages Work<\/a><\/li><li class=\"\"><a href=\"#htoc-1111111111111111111111\">How to Diagnose Your Error&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-11111111111111111\">Common SMTP \/ Bounce Codes and Their Meanings&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-111111\">Common Error Messages, What They Mean and How to Fix Them<\/a><ul class=\"ht_toc_child_list\"><li class=\"\"><a href=\"#htoc-111\">1. \u201c550 Sender Verify Failed\u201d&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-1111\">2. \u201cAuthentication Failed\u201d&nbsp;&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-11111111\">3. \u201cCertificate Name Mismatch\u201d or \u201cSecurity Certificate Warning\u201d&nbsp;&nbsp;&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-11111111111\">4. \u201cIP Address Has Changed\u201d&nbsp;<\/a><\/li><\/ul><\/li><li class=\"\"><a href=\"#htoc-111111111111111111\">Outlook and Client-Side Error Examples&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-111111111111111111111\">Quick Fixes and Troubleshooting&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-111111111111111111111111\">When The Error Isn\u2019t Yours&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-1111111111111111111111111\">FAQs&nbsp;<\/a><\/li><li class=\"\"><a href=\"#htoc-1111111111111111111111111111111\">Additional Resources&nbsp;<\/a><\/li><\/ul><\/div><\/div>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-\"><strong>How Email Error Messages Work<\/strong><\/h2>\n\n\n\n<p>Email servers communicate via protocols like <a href=\"https:\/\/1grid.co.za\/knowledge\/understanding-smtp-ports-and-ssltls-encryption\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>S<\/strong><\/a><a href=\"https:\/\/1grid.co.za\/knowledge\/understanding-smtp-ports-and-ssltls-encryption\/\"><strong>MTP<\/strong><\/a>, <a href=\"https:\/\/1grid.co.za\/knowledge\/what-is-the-difference-between-pop-and-imap\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>POP<\/strong><\/a>, and <a href=\"https:\/\/1grid.co.za\/knowledge\/what-is-the-difference-between-pop-and-imap\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>IMAP<\/strong><\/a>. When something goes wrong, they respond with status codes as 3-digit numbers that signal success, temporary issues, or permanent failures. This is what is called a<strong> <a href=\"https:\/\/1grid.co.za\/knowledge\/knowledge\/why-emails-bounce-back-error-messages-and-how-to-fix-them\/#htoc-hard-bounce-vs-soft-bounce-the-most-important-difference\">soft or hard bounce<\/a><\/strong>, depending on the issue and failure type.\u00a0<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-1\">Codes beginning with <strong>2xx<\/strong>: success \/ no error&nbsp;<\/li>\n\n\n\n<li id=\"htoc-codes-with-4xx-temporary-failures-retry-possible\">Codes with<strong> 4xx<\/strong>: temporary failures (retry possible)&nbsp;<\/li>\n\n\n\n<li id=\"htoc-11\">Codes with <strong>5xx<\/strong>: permanent errors needing action&nbsp;<\/li>\n<\/ul>\n\n\n\n<p><strong>TIP:<\/strong> Enhanced codes (e.g. 5.1.1, 5.2.1) give more detailed failure information, and you can find more detailed SMTP codes <strong><a href=\"https:\/\/1grid.co.za\/knowledge\/a-guide-to-smtperror-codes\/\" target=\"_blank\" rel=\"noreferrer noopener\">here<\/a><\/strong>.\u00a0<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-1111111111111111111111\"><strong>How to Diagnose Your Error&nbsp;<\/strong><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-11111111111111111111111\">Locate the full error (bounce email or client dialog) and note the code and description.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-determine-if-it-s-a-sending-or-receiving-error\">Determine if it\u2019s a <strong>sending<\/strong> or <strong>receiving<\/strong> error.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-match-the-code-with-the-table-above-or-in-this-guide\">Match the code with the table below, or an error in this guide.\u00a0<\/li>\n\n\n\n<li id=\"htoc-cross-check-your-settings-server-names-ports-ssl-tls-username-password\">Cross-check your <strong><a href=\"https:\/\/1grid.co.za\/knowledge\/settings-to-configure-your-1grid-email-accounts-across-devices\/\">configuration settings<\/a><\/strong> (<a href=\"https:\/\/1grid.co.za\/knowledge\/recommended-server-settings-for-email-encryption-ports\/\"><strong>server names<\/strong><\/a>, <a href=\"https:\/\/1grid.co.za\/knowledge\/recommended-server-settings-for-email-encryption-ports\/\"><strong>ports<\/strong><\/a>, <a href=\"https:\/\/1grid.co.za\/knowledge\/recommended-server-settings-for-email-encryption-ports\/\"><strong>SSL\/TLS<\/strong><\/a>, username\/password).\u00a0<\/li>\n\n\n\n<li id=\"htoc-try-basic-actions-like-resending-again-later-for-4xx-codes\">Try basic actions like resending again later (for 4xx codes).&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-11111111111111111\"><strong>Common SMTP \/ Bounce Codes and Their Meanings&nbsp;<\/strong><\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td><strong>Code<\/strong>&nbsp;<\/td><td><strong>What It Means<\/strong>&nbsp;<\/td><td><strong>What to Try<\/strong>&nbsp;<\/td><\/tr><tr><td>421&nbsp;<\/td><td>Service not available (temporary)&nbsp;<\/td><td>Transaction failed\/blocked\u00a0<\/td><\/tr><tr><td>450&nbsp;<\/td><td>Mailbox unavailable or server busy&nbsp;<\/td><td>Try later, verify that the mailbox exists&nbsp;<\/td><\/tr><tr><td>451&nbsp;<\/td><td>Local processing error&nbsp;<\/td><td>Retry again later; contact the recipient server if the issue persists&nbsp;<\/td><\/tr><tr><td>452&nbsp;<\/td><td>Insufficient system storage&nbsp;<\/td><td>The recipient needs to free space or try again later&nbsp;<\/td><\/tr><tr><td>550&nbsp;<\/td><td>Transaction failed\/blocked&nbsp;<\/td><td>Verify the recipient address, check DNS \/ MX&nbsp;<\/td><\/tr><tr><td>554&nbsp;<\/td><td>Transaction failed \/ blocked&nbsp;<\/td><td>Mailbox not found\/rejected&nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-111111\"><strong>Common Error Messages, What They Mean and How to Fix Them<\/strong><\/h2>\n\n\n\n<p>Here are some common error messages we\u2019ve highlighted for you.\u00a0<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"htoc-111\"><strong>1. \u201c550 Sender Verify Failed\u201d<\/strong>&nbsp;<\/h3>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>What This Means and How To Fix It<\/strong><\/summary>\n<p id=\"htoc-11111\"><strong>Full Mailbox <br><\/strong>Mailbox storage quotas are set to 250MB by default, but some plans allow you to turn off the limit and set mailbox quotas to \u201cunlimited.\u201d If an email account is at or past its capacity, sending out from it won\u2019t work, and you\u2019ll get a \u201cSender Verify Failed\u201d error. <br><br><strong><a href=\"https:\/\/1-grid.com\/knowledge\/cpanel-how-to-increase-your-email-storage-space\/\">Check the mailbox quota<\/a> <\/strong>of an email account.<\/p>\n\n\n\n<p id=\"htoc-1111111\"><strong>Mail Routing<\/strong><br>Your domain\u2019s email routing setting may be incorrect. <br><br><a href=\"https:\/\/1-grid.com\/knowledge\/cpanel-how-to-change-mx-records-and-email-routing\/\"><strong>Check your MX records<\/strong><\/a>.<\/p>\n<\/details>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"htoc-1111\"><strong>2. <strong>\u201cAuthentication Failed\u201d<\/strong>&nbsp;<\/strong>&nbsp;<\/h3>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>What This Means and How To Fix It<\/strong><\/summary>\n<p id=\"htoc-111111111\">An \u201cAuthentication Failed\u201d error means the email server cannot verify that your email access is authorised. This is typically due to a mistyped password, but it can also be caused by an incorrect username, connecting to the wrong server, or blacklisting.<\/p>\n\n\n\n<p id=\"htoc-1111111111\">Follow these steps to resolve the issue:&nbsp;<br><br>1. <a href=\"https:\/\/1-grid.com\/knowledge\/cpanel-how-to-change-reset-email-passwords\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Reset your email password<\/strong><\/a>.&nbsp;<br>2. If you\u2019ve recently changed where your domain points, or if you\u2019ve upgraded or downgraded your hosting plan, wait up to 4 to 48 hours for your new DNS settings to <a href=\"https:\/\/dnschecker.org\/#NS\/\"><strong>propagate worldwide<\/strong><\/a>.&nbsp;<br>3. It\u2019s also possible that your<a href=\"https:\/\/1-grid.com\/knowledge\/how-to-check-if-my-ip-is-blacklisted-2\/\" target=\"_blank\" rel=\"noreferrer noopener\"> <strong>local IP is blacklisted<\/strong><\/a>. Wait 24 hours and try again, using <strong><a href=\"https:\/\/1grid.co.za\/knowledge\/?s=webmail&amp;ht-kb-search=1&amp;lang=\">Webmail<\/a> <\/strong>in the meantime.&nbsp;&nbsp;<\/p>\n<\/details>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"htoc-11111111\"><strong>3. <strong><strong>\u201cCertificate Name Mismatch\u201d or \u201cSecurity Certificate Warning\u201d<\/strong>&nbsp;<\/strong>&nbsp;<\/strong>&nbsp;<\/h3>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>What This Means and How To Fix It<\/strong><\/summary>\n<p id=\"htoc-111111111111\">This error is a warning from your email application that the certificate for SSL that the server uses doesn\u2019t match the name that your email application was expecting.&nbsp;&nbsp;<\/p>\n\n\n\n<p id=\"htoc-1111111111111\">We\u2019ve created a quick guide to help with<strong> <a href=\"https:\/\/1grid.co.za\/knowledge\/troubleshooting-a-security-certificate-warning-pop-up-in-outlook\/\" target=\"_blank\" rel=\"noreferrer noopener\">troubleshooting a Security Warning Pop-Up in Outlook<\/a><\/strong>.&nbsp;<\/p>\n<\/details>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"htoc-11111111111\"><strong>4. \u201cIP Address Has Changed\u201d<\/strong>&nbsp;<\/h3>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>What This Means and How To Fix It<\/strong><\/summary>\n<p id=\"htoc-11111111111111\">Every time you log into your Webmail account, your computer\u2019s <a href=\"https:\/\/whatismyipaddress.com\/ip-lookup\"><strong>IP address<\/strong><\/a> is recorded. If your IP address changes while you\u2019re logged in, Webmail won\u2019t recognise your new connection as valid and will automatically log you out. <\/p>\n\n\n\n<p id=\"htoc-111111111111111\">The easiest way to fix this error is to log in again so your new IP address is recorded.<\/p>\n\n\n\n<p id=\"htoc-1111111111111111\">However, if you\u2019re seeing this error frequently, here are a few other things you can do:&nbsp;<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>If possible, try using another internet connection, such as mobile data or Wi-Fi, and try again.&nbsp;<\/li>\n\n\n\n<li>If this resolves the issue, contact your Internet Service Provider (ISP) and ask to be given a<strong> <a href=\"https:\/\/1grid.co.za\/knowledge\/whats-the-difference-between-a-static-and-dynamic-address\/\">static (unchanging) IP address<\/a> <\/strong>so it won\u2019t change while you\u2019re logged in to Webmail.&nbsp;<\/li>\n\n\n\n<li>If that isn\u2019t possible, ask your ISP if the \u201c<a href=\"https:\/\/www.manageengine.com\/products\/oputils\/tech-topics\/dhcp-lease-time.html\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>DHCP lease time<\/strong><\/a>\u201d can be increased, which will allow your login sessions to be longer.&nbsp;<\/li>\n<\/ul>\n<\/details>\n\n\n\n<p><strong>NOTE: <\/strong>Not all errors are failures. For example: <strong>250<\/strong> means \u201cOK, message accepted\u201d. More detailed codes can be found<strong> <a href=\"https:\/\/support.optimizely.com\/hc\/en-us\/articles\/4413205564429-SMTP-codes-and-error-messages\" target=\"_blank\" rel=\"noreferrer noopener\">here<\/a><\/strong>.&nbsp;<\/p>\n\n\n\n<p><strong>TIP: <\/strong>Should you require more information regarding email errors, you can check out our <a href=\"https:\/\/1-grid.com\/knowledge\/email-troubleshooting-guide\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Troubleshooting Guide<\/strong><\/a>.&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-111111111111111111\"><strong>Outlook and Client-Side Error Examples&nbsp;<\/strong><\/h2>\n\n\n\n<p>Client-side errors mean something is wrong with the user&#8217;s browser, device, or local network, preventing the request from being processed correctly by the server, rather than a problem on the server itself. These are often indicated by 4xx HTTP status codes, such as a <a href=\"https:\/\/en.wikipedia.org\/wiki\/HTTP_404\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>404 Not Found error<\/strong><\/a>, and can be caused by issues like JavaScript errors, corrupted cache, or network connectivity problems.&nbsp;<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li id=\"htoc-1111111111111111111\"><strong><a href=\"https:\/\/learn.microsoft.com\/en-us\/answers\/questions\/4664979\/outlook-2021-will-not-send-mail-receiving-ok-get-e\">0x8004210B<\/a><\/strong> is a timeout sending mail error in Outlook.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-0x8004010f-is-as-a-result-of-failures-due-to-profile-mailbox-access-issues\"><strong><a href=\"https:\/\/learn.microsoft.com\/en-us\/troubleshoot\/outlook\/synchronization\/error-0x8004010f-when-sending-or-receiving-emails\">0x8004010f<\/a><\/strong> is a result of failures due to profile\/mailbox access issues.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-there-was-an-error-sending-the-message-is-a-generic-send-receive-failure-in-outlook\">\u201cThere was an error sending the message\u201d is a generic send\/receive failure in Outlook.&nbsp;<\/li>\n\n\n\n<li id=\"htoc-11111111111111111111\">In Webmail or a mobile app, you can commonly receive authentication errors (\u201clogin failed\u201d), \u201cserver not found\u201d, or <a href=\"https:\/\/1grid.co.za\/knowledge\/troubleshooting-a-security-certificate-warning-pop-up-in-outlook\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>SSL Certificate Warnings<\/strong><\/a>.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-111111111111111111111\"><strong>Quick Fixes and Troubleshooting&nbsp;<\/strong><\/h2>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Invalid Recipient<\/strong><\/summary>\n<ul class=\"wp-block-list\">\n<li>Correct the email address or remove any invalid addresses.&nbsp;<\/li>\n<\/ul>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>DNS \/ MX Record Issues<\/strong><\/summary>\n<ul class=\"wp-block-list\">\n<li>Ensure your domain\u2019s mail settings are correct.<\/li>\n<\/ul>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Authentication Failures<\/strong><\/summary>\n<ul class=\"wp-block-list\">\n<li>Reset the password, ensure \u201cuse same credentials\u201d in the SMTP settings.<\/li>\n<\/ul>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>SSL \/ Certificate Mismatch<\/strong><\/summary>\n<ul class=\"wp-block-list\">\n<li>Ensure your mail server\u2019s certificate matches the hostname.<\/li>\n<\/ul>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Firewall \/ Antivirus Interference<\/strong><\/summary>\n<ul class=\"wp-block-list\">\n<li>Temporarily disable or adjust for the mail ports.&nbsp;<\/li>\n<\/ul>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Retry After Delay<\/strong><\/summary>\n<ul class=\"wp-block-list\">\n<li>For <a href=\"https:\/\/learn.microsoft.com\/en-us\/azure\/architecture\/best-practices\/transient-faults\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>transient errors<\/strong><\/a> (4xx).&nbsp;<\/li>\n<\/ul>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Persistent Rejects (5xx)<\/strong><\/summary>\n<ul class=\"wp-block-list\">\n<li>Require changes before resending.&nbsp;<\/li>\n<\/ul>\n<\/details>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-111111111111111111111111\"><strong>When The Error Isn\u2019t Yours&nbsp;<\/strong><\/h2>\n\n\n\n<p>Some errors are beyond your control (e.g. recipient server down, network issues). Some techniques, like <a href=\"https:\/\/en.wikipedia.org\/wiki\/Greylisting\"><strong>greylisting<\/strong><\/a>, can result in 4xx temporary rejections even though your configuration is okay.&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-1111111111111111111111111\"><strong>FAQs&nbsp;<\/strong><\/h2>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>I see the error \u201c550 5.1.1 Mailbox not found.\u201d What should I do?<\/strong><\/summary>\n<p id=\"htoc-11111111111111111111111111\">This usually means the recipient address is invalid, or the mailbox was deleted. Double-check spelling, contact the recipient, or verify their server.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>My Outlook shows \u201c0x8004210B \u2013 send timeout.\u201d<\/strong><\/summary>\n<p id=\"htoc-111111111111111111111111111\">This happens when Outlook times out connecting to the SMTP server. Check your SMTP server, port, SSL settings, and<strong> <a href=\"https:\/\/www.speedtest.net\/\" target=\"_blank\" rel=\"noreferrer noopener\">network stability<\/a><\/strong>.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>I got \u201c421 Service not available.\u201d&nbsp;<\/strong><\/summary>\n<p id=\"htoc-1111111111111111111111111111\">This is a temporary server issue. Wait and try sending again later.<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Why did my email get \u201c554 Transaction failed\u201d?<\/strong><\/summary>\n<p id=\"htoc-11111111111111111111111111111\">This often means your message was blocked by <strong><a href=\"https:\/\/1grid.co.za\/knowledge\/blocked-via-mailchannels-due-to-spam\/\" target=\"_blank\" rel=\"noreferrer noopener\">spam filter rules<\/a> <\/strong>or <a href=\"https:\/\/1grid.co.za\/knowledge\/how-to-avoid-mailchannels-blocks\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>sender policy<\/strong><\/a>. Check content, sender IP reputation, or contact the recipient\u2019s admin.&nbsp;<\/p>\n<\/details>\n\n\n\n<details class=\"wp-block-details is-layout-flow wp-block-details-is-layout-flow\"><summary><strong>Do I always have to be technical to use this?&nbsp;<\/strong><\/summary>\n<p id=\"htoc-111111111111111111111111111111\">No, you can copy the error details and follow the steps above. If unsure, send the error message with screenshots, where possible, to Support, as it helps us diagnose faster.&nbsp;<\/p>\n<\/details>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"htoc-1111111111111111111111111111111\"><strong>Additional Resources&nbsp;<\/strong><\/h2>\n\n\n\n<p><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>&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> <\/strong>&nbsp;<br><a href=\"https:\/\/1grid.co.za\/knowledge\/troubleshooting-a-security-certificate-warning-pop-up-in-outlook\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Troubleshooting a Security Certificate Warning Pop-Up in Outlook<\/strong><\/a><strong> <\/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\/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=mailchannels&amp;ht-kb-search=1&amp;lang=\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>MailChannels FAQs<\/strong><\/a>&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-11111111111111111111111111111111\"><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>Understanding email error messages and figuring out how to fix them doesn\u2019t have to feel so 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\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Every mail server and client is unique, and so are their error responses. When you send or receive email, errors may occur, and often the message you see contains the clue you need to fix it. Because we know it\u2019s not always easy to decipher what they\u2019re trying to tell&#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":[1491,1492,336,344,369,616,621,928,1007,1046,1118],"class_list":["post-24030","ht_kb","type-ht_kb","status-publish","format-standard","hentry","ht_kb_category-email","ht_kb_category-email-troubleshooting","ht_kb_tag-bounce-codes","ht_kb_tag-client-errors","ht_kb_tag-email","ht_kb_tag-email-hosting","ht_kb_tag-error","ht_kb_tag-mean","ht_kb_tag-message","ht_kb_tag-smtp","ht_kb_tag-they","ht_kb_tag-troubleshooting","ht_kb_tag-what"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.0 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Email Error Messages: What Do They Mean and How to Fix Them -<\/title>\n<meta name=\"description\" content=\"This article provides you with information regarding common email error messages. 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