When+I+send+an+email,+for+some+reason+it+is+sent+back+to+me+and+fails.+What's+going+on

I sent an email three times and each time it stuck in the outbox file and produced an error message saying it cannot send quoting my own email address as the destination.

Hello Jim,
could you please provide the whole text of the returned email? Sounds like your message might be rejected by your mail server, but it’s hard to tell without more infromation.
Is there any message in the Tools>Operations>Error tab?

Regards,
Olivia