You have not given us enough information to actually assist you. Please
help us to help you by reading and following the posting guidelines in
this thread: Please read before requesting assistance.You may want to provide us some screen shots (sanitize your server and user names) showing us how you have things configured in: Admin panel -> Settings -> Emails -> Default Outgoing Emailand in: Admin panel -> Emails -> your emails. (more speifically the SMTP Settings section)