Here are the general email settings for any client (Outlook, Thunderbird, Mac, iPad, etc.):
Display Name: Your Name or Company Name
Email address: email@example.com
Username/Account: firstname.lastname@example.org (MUST BE YOUR FULL EMAIL ADDRESS)
Password: your password
Type of connection:IMAP (or POP3, but IMAP syncs across devices)
Incoming mail server: yourwebsite.com
Outgoing mail server: yourwebsite.com
Incoming mail port: 143
Outgoing mail port: 26
Outgoing mail server requires authentication.
No SSL boxes should be checked.
Do not use SPA (secure password authentication).
If you see pop-up windows related to verifying the identity or certificate, simply hit Continue as needed. This is related to the name of the server being different than your website name. It is not a security issue, and can safely be ignored.
NOTE to iPhone and iPad users: If you have already setup your email incorrectly, you cannot simply update the settings to be correct. Instead, you need to fully delete the account from the iPad, perform a hard reset, and recreate the entire account with the proper settings.