I'm apparently unable to get the correct combination of Port, Server and/or SMTP settings to allow me to send mail. I can receive mail just fine. Any insight?

Tried both 'Exchange Active Sync' and regular setup w/ POP and SMTP settings:

Active Sync:
Port - tried 587, 25, 110
Domain - tried domain.com
Server Address -tried mail.domain.com AND domain.com

Regular:
Have tried both POP and IMAP protocols
POP server - mail.domain.com (receive mail works fine)
SMTP server - tried mail.domain.com AND smtp.domain.com
Server Port - Port - tried 587, 25, 110

The main error that I receive is "Authentication Failed. Please verify username and/or password.", but it's not a username/pw issue and ultimately when I get the right combination to allow setup it appears to be successful, but I just can't send mail. Msgs appear to send and do appear in "Sent" folder, but are never received....