That's not a Perl error.

It's not even an error that indicates no mail is send to AOL or hotmail. It's an error that indicates mail was attempted to be delivered, but it was refused, for the reason indicated in the error message.

I'm baffled why you think it's a Perl error. It's probably not even a sendmail error. It more looks like a data error to me. Are you sure you are actually mailing to the address you think you are mailing to?

Abigail