Problem adding an additional e-mail address to Outlook

Hello,

I have one e-mail setup with Outlook and trying to add an additional e-mail that is a domain e-mail address with a .net.  When  I add account and connect with this .net e-mail, it states "couldn't logon to the incoming (POP/IMAP) server.  Please check your e-mail address and password and try again"?  

Any assistance would be appreciated.  Thanks in advance.

Dan