For most email clients this pattern works:
Mail Server Username: (email)@(domain) e.g. info@123host.com.au
Incoming Mail Server: mail.(domain) e.g. mail.123host.com.au
Outgoing Mail Server: mail.(domain) NOTE: server requires authentication and should use port 26
Supported Incoming Mail Protocols: POP3, POP3S (SSL/TLS), IMAP, IMAPS (SSL/TLS)
Supported Outgoing Mail Protocols: SMTP, SMTPS (SSL/TLS)