Most times the "mail.example.com" should work fine on the SMTP settings, however many ISPs (Internet Service Provider) may not allow the use of an external SMTP address.

This is actually becoming more common as many ISP's are starting to disable SMTP in an effort to cut down on spam. They require you to use the ISP's own mail sending.

If you are able to receive mail but unable to send mail, you will want to contact your ISP and see if they have blocked "Port 25" (this is the SMTP Port). If they have, they will either have steps to get around it, or will unlock it for you if you tell them that you require SMTP to send out mail through your own domain name.

ProExe can provide a solution (chargeable) if your own ISP blocks port 25. We can provide you with an SMTP connection for your outgoing email.