I sent an email to wrong amail address...and it keeps trying to send it

I sent an email to .oal instead of .aol by accident. It understandably bounced back to me as it was an unrecognizable email. But it seems everyday it keeps trying to send that email and i have no idea how to stop it.

I have deleted the original message but it keeps trying to send it with a bounce back message telling me it cannot be sent.

How do i stop it? Or do i just let it run it's course and it will eventually stop?