Troubleshooting

To protect your domain’s reputation and ensure that your emails are delivered successfully, MailChannels applies email sending limits to every domain. These limits...

If you’ve ever seen errors like “Cannot connect to SMTP server” or “Encryption mismatch”, the issue is usually not your mailbox; it’s the port or...

SMTP error codes do not automatically mean your email, domain or server is broken – most are configuration or recipient-side...

Email bounce-back errors can feel frustrating, especially when the message doesn’t clearly explain what went wrong. Most bounce errors do not mean...

If you can receive but are unable to send emails, the issue is usually related to your outgoing mail server (SMTP) configuration. ...

If you’ve received a bounce message saying: “Delivery failed: Retry timeout exceeded”, it means your email server tried multiple times to deliver your message, but the receiving...

If you’ve seen SMTP Error 550: Message Rejected by Server, your email was blocked by the receiving mail server. That’s frustrating, but it doesn’t mean something is...

If you see SMTP Error 451: Temporary Local Problem, it means the receiving mail server temporarily rejected your message, but may accept it...

If you’re seeing SMTP Error 535: Authentication Failed, your email client cannot log into the outgoing mail server.  This guide will help you:  Nothing...

If you’ve received SMTP Error 421, it means the receiving mail server is temporarily unavailable or too busy to process your email.  This...