Error Description
SMTP error 511 is a permanent or "5xx" error code returned by a mail server to indicate that it has rejected an email message because it could not relay or deliver the message to the intended recipient. This error signifies that the server is unable to route the email to the specified recipient address.
What's Causing This Error?
SMTP error 511 is typically caused by one or more of the following reasons:
- Invalid recipient address: The recipient's email address provided in the "RCPT TO" command or the "To:" field of the email message is incorrect, improperly formatted, or does not exist.
- Routing issues: The server may be experiencing problems with its email routing, which prevent it from correctly directing email messages to their intended recipients.
- DNS issues: Domain Name System (DNS) problems or incorrect DNS settings can also lead to SMTP error 511, making it difficult for the server to resolve recipient domains.
How to fix SMTP Error 511?
- Verify recipient address: Ensure that the recipient's email address is spelled correctly, is complete, and includes the correct domain name. Correct any typographical errors or formatting issues.
- Investigate routing issues: If the error is related to routing problems, you may need to contact your email administrator or hosting provider to resolve the issue.Address
- DNS issues: If DNS problems are the root cause, work with your DNS provider or administrator to correct any DNS misconfigurations or issues affecting email routing.
SMTP Error 511 Examples
Example 1: "511 5.1.1 recipient@example.com: Invalid recipient address. Check recipient details."
Example 2: "511 5.4.2 Routing issue. Unable to relay the message to recipient@example.com."
Example 3: "511 5.7.3 DNS problem. Email routing to recipient@example.com is currently unavailable."
