If you are getting the error “553 sorry, that domain isn’t in my list of allowed rcpthosts.” To send an email, we require you to use SMTP authentication. This is a security measure to prevent SPAM from being sent through our mail server.
In your email program, you should be able to click a checkbox to enable smtp authentication. The login information for smtp authentication should be the same as the incoming mail server login information.
We highly recommend that you use the E-mail Setup Wizard to setup your e-mail program to properly send and receive e-mail.