Setting up email on your phone: IMAP or POP?

That choice decides whether you see the same thing on every device. For almost everybody the answer is IMAP.

IMAP

Your mail stays on the server and your devices show the same mailbox. What you delete on your phone is also gone on your computer. That is what most people expect.

POP

Your mail is downloaded and often removed from the server. On a second device it is then no longer there. Only useful if you work on one device and want everything stored locally.

What you need

The incoming and outgoing server, your full address as the username, and encryption switched on. A port without encryption sometimes still works, but it sends your password in readable form.

When it does not work

Most often it is the username: the part before the at sign instead of the full address. Then test whether sending requires authentication — many setups fail only on outgoing mail.