My email quit working on my ipad. I deleted the account but now I can not set up email using att as my email host.

Is anyone having issues using either ATT email or sbcglobal.net email on ipad. My email quit working on my ipad on Wednesday. I deleted the account and have been unable to reinstall my sbcglobal.net email on 2 different ipads and an iphone. no issues with other email accounts like gmail.