Sending email failed due to the following error: At least one recipient isn't valid.

I sent an email to an incorrect address some time back, when I got the undelivered message I resent using the correct address and deleted the email to the incorrect one. I now keep getting error messages to say the incorrect email is still trying to be sent, but I cant see it in my outbox. How do I resolve this

This is nothing to do with the email client, but rather an action of your email server.

Sometimes a server will notify you that it can’t send to that address, but it hasn’t given up yet. It will retry a few times, and then send you a message to say that it has finally given up. Depends on the server how many times and at what interval it will re-try.

Best is to see where the notification messages comes from and contact that server admin (probably your email provider) if you don’t want to receive further messages from them.