Generally use IMAP settings for mobile devices. Here are the settings:
Username: Your FULL email address
Password: Your assigned email password (you can change this if you want - See How To Change My Email Password)
Incoming Mail Server: mail.yourdomain.com (e.g. mail.50bubbles.com)
Incoming Mail SSL: None
Incoming Mail Port #: 143
Outgoing Mail Server: mail.yourdomain.com (e.g. mail.50bubbles.com)
Outgoing Mail SSL: None
Outgoing Mail Port #: 587
Security: Outgoing Mail using same login credentials as incoming mail (username and password)