Here are a few simple recommendations for dealing with returned email messages, especially if there are unfamiliar returned email error messages.

Do

• Contact the person you're trying to mail by other means. They may not know they are bouncing mail.
• Keep the returned message. It can help our tech support staff solve the problem quickly. It also (usually) contains the original message, which you may need to resend after the problem is fixed.
• Try to send yourself a test message if someone tells you your email account is bouncing mail. If possible, use an email account from a different domain than the account you are trying to test.

Don't

• Try to respond to the bounce message; it will rarely yield any results.
• Continue trying to mail users after 2 or 3 tries (for permanent errors) or a week (for temporary errors).
  (note: This is doubly true if you run a mailing list. Remove subscribers when they begin bouncing with permanent failures. They have probably already resubscribed with a new address, and have not removed their old address.)
• Assume that just because you can send a message to yourself that everyone else can. Email that does not leave your domain is usually handled differently than email that originates externally.