Docs Error Library Email Delivery Errors Error 521: Server Does Not Accept Mail

Error 521: Server Does Not Accept Mail

What Is Causing This Error?

‘Error 521: Server does not accept mail’ indicates that a mail server isn’t set up to accept incoming emails.

Often seen in mail relays, these servers act as intermediaries, transferring the emails to another server rather than handling the final delivery themselves. In simple terms, when you encounter this error, the server is saying it’s passing the email along in the relay chain but isn’t its final destination.

Resolving the Error – Solution

Before attempting to fix this error, it’s crucial to first verify the actual delivery status of the emails sent. There’s a chance the emails have been successfully relayed further and delivered to the intended recipients.

If, however, recipients confirm they haven’t received the emails, the next step is pinpointing the reason behind the recipient’s mail server’s refusal. This typically involves reaching out to the mail server administrators to understand and rectify the issue at hand.

That’s it! Now you know the common causes of the 521 error and how to resolve it.

If you’d like to learn how to troubleshoot other common errors, check out the following tutorials: