550 mail is rejected by recipients

A common issue!

When 550 mail is rejected by recipients, it usually means that the email server or the recipient's email account is rejecting the email due to a specific reason. The 550 error code is a generic code that can have various causes. Here are some possible reasons:

  1. Invalid email address: The recipient's email address may be invalid, non-existent, or not properly formatted.
  2. Domain not found: The domain name of the recipient's email address may not exist or may be misspelled.
  3. Email address blocked: The recipient's email address may be blocked by their email provider or by a spam filter.
  4. Content filtering: The email content may be flagged as spam or contain keywords that trigger a spam filter.
  5. Email size or attachment issues: The email may be too large or contain attachments that exceed the recipient's email server's limits.
  6. Authentication issues: The email may not be authenticated properly, which can cause the recipient's email server to reject it.
  7. Blacklisting: The IP address of your email server or the sending domain may be blacklisted, which can cause emails to be rejected.

To troubleshoot the issue, you can try the following:

  1. Check the email address: Verify that the recipient's email address is valid and properly formatted.
  2. Check the domain: Verify that the domain name of the recipient's email address exists and is properly configured.
  3. Check the email content: Review the email content to ensure it is not flagged as spam or contains any keywords that may trigger a spam filter.
  4. Check the email size and attachments: Verify that the email size and attachments are within the recipient's email server's limits.
  5. Check authentication: Ensure that your email server is properly authenticated and configured.
  6. Check blacklisting: Verify that your email server's IP address or the sending domain is not blacklisted.
  7. Contact the recipient: Reach out to the recipient and ask them to check their email settings or contact their email provider to resolve the issue.

If you're still having trouble, you may want to consider consulting with your email provider or a network administrator for further assistance.