The whole category in one page.
THE DECISION THAT MATTERS MOST
IMAP, not POP.
POP downloads mail to one device and removes it from everywhere else. It is the cause of most "my email disappeared" reports.
WHERE TO GET SETTINGS
cPanel, Email Accounts, connect devices.
Use those exact values. Use manual setup, not automatic, which frequently guesses wrongly.
THE MOST COMMON SETUP ERROR
Username must be the full email address, not just the part before the at sign.
THE SECOND MOST COMMON
Outgoing authentication not enabled. That is why sending fails while receiving works.
THE DIAGNOSTIC THAT SETTLES MOST PROBLEMS
Does webmail work?
If yes, the server is fine and the problem is the client.
FOR SENT MAIL MISSING ON OTHER DEVICES
Map Sent, Drafts and Trash to the server folders on every device.
ALWAYS USE ENCRYPTED SETTINGS
Never disable certificate checking to make a connection work.
WHEN YOU CHANGE A MAILBOX PASSWORD
Update every device, and your website's SMTP configuration.
A device with the old password can get your address temporarily blocked.
WATCH YOUR QUOTA
A full mailbox silently rejects incoming mail.