Mail Stopped receiving or sending with 10.3.9
Mail will not find server or send mail on my Graphite G4 OS X 10.3.9 once Apple migrated to Mail.me
Tried to change to IMAP to no avail
Mac OS X (10.3.x)
me.com is no longer valid. Apple switched again to iCloud.
http://support.apple.com/kb/ts4002
You may want to consider using your internet provider's outgoing mail server instead.