Need help with att.net mail and new secure key for iphone email.

Thanks for the comment and I have tried setting it up as an imap account with the login information of user name, password on my account imap .... when I do this I keep getting an error message that user name or password for imap.mail.   What is confusing is from the website they say to go to "other" but if I login on my phone it would appear that I should be going to yahoo.  So.... I am confused and what makes me a little mad is a) I didn't get the email from Att.net about changing from previous method of security to either a secure key for my outlook email on anything on my phone.  I have successfully done my outlook and created a secure key but as of this moment my iphone does not work.  So if you can give me a clue where I might find "good" directions to get this done that would be great because as of this moment, I have lost my att mail box under password and accounts which is not something that will "kill me" it is just frustrating.

Thanks for help,

Hello everyone.. first thank you for all the help.. and I have found the fix... Since I used a secure key to start with, I needed to follow that thru on the iphone.  I made two changes which if you start with the defaults, you get the one for imap and smtp which it thinks is the default...yahoo.... once I changed the smtp and imap servers and put in the secure key I created for phones, it worked just fine...

Thanks for the clues that worked.