How do I set up Mail for ATT email? It was previously working and does not work now.

Question

I had my ATT email working.  It will only let me set it up as an IMAP account via Yahoo, however the ATT web site says that I should be setting it up as a POP3.  Either way it's a no go.  Has anyone had an ATT IMAP email account that worked and all of a sudden decided not to work?

Answer 1

I see dropdown menus for SMTP SSL and IMAP/POP SSL. I have them both set as "Require"
Do not to this if your server is handling incoming mail from outside your network.
Few remote mail servers will use SSL, so if your server requires SSL then you will not be able to receive mail from outside your domain.
'Use', on the other hand, advertises the fact your server supports SSL, so clients and remote servers can use if if they like, but this still allows other mail in.
What should "Authentication" be - "Login" or "Plain"
Do not use Plain unless you absolutely trust all your clients (i.e. they're all on a LAN or all using SSL). Plain sends an unencrypted password over the wire, which is susceptible to sniffing.
what will the client be using?
Whatever you set it to.
The client complains about a correct root certificate not being installed).
Are you using a self-signed certificate? if so, you're going to get that unless you do a lot of extra work. Getting a real certificate from a trusted authority should resolve this.
As for the slow connections, the use of SSL shouldn't significantly impact connection or delivery/transfer times, so something else is amiss.