If you wish to send out e-mail messages through an email address with your own domain, you have to make sure that the provider will give you access to their SMTP server. The latter is the software which permits e-mail messages to be transmitted. SMTP is an abbreviation for Simple Mail Transfer Protocol and it deals with all outbound emails from apps, webmail and contact web forms. When a message is sent out, the SMTP server confirms with all of the DNS servers throughout the world where the e-mails for the receiving domain name are taken care of and when it acquires this info, it will connect into the remote POP/IMAP server to check if the recipient mail box is out there. If it does, the SMTP server sends the email body and then the receiving server sends it to the mail box in which the recipient can open it up and read it. Without an SMTP server on your server, you will not be capable to send out emails in any way.