unwanted adress being forwar

Hello, BobT.47.

Thank you for posting in Apple Support Communities. We understand that you've been experiencing issues with an email bouncing back because of an incorrect recipient. We'd like to see if we can help.

We encourage yo to start with the "If you can't send mail from the Mail app on your Mac > If your recipient doesn't receive your message" section of this article:

If iCloud Mail isn't working - Apple Support

The same steps are valid even if the account isn't an iCloud account.

Warmest Regards.

Bob,

Hopefully removing the address helped and your outgoing email is no longer bouncing back. If not, let us know. We want to make sure you're getting the most efficiency out of your Mac.

Cheers.