Att pacbell abc email on ipads
When you "add new account" select "other" or it populated the server configuration for you and you cannot change it. Once you select "other" enter your smtp server such as smtp.att.yahoo.com or whatever your smtp server is. Add username and password and it should work. In my case it did not even ask for all the detail such as SSL and SPA and the specific ports to be used.
If you choose the wrong kind of account it will never accept the configurations and you just get error messages endlessly. Just delete the account and start over. Don't get lead astray by the Yahoo and ATT selections they offer