Contacted my ISP, BlueHost, who suggested I change outgoing port to 25 or 26. Nothing has worked.
Is the email a standard email like @yahoo.com, @sbcglobal, @hotmail.com etc? Or a proprietary. custom domain email? What settings does the email provider suggest? Are you trying to set this up as IMAP or POP3?
25 is smtp server setting.
It is a proprietary custom email.
talk to your it folks.
Email Application Setup
Does that help? I use several custom domain email addresses, and sometimes I need to try several settings before they finally work.