Incoming / Outgoing mail servers stopped working

This can occur for many reasons including a conversion from DSL to U-verse. The U-verse server uses different settings.

Be sure you are using the correct settings. The correct settings can be found in this article.

Server Settings

Also, this discussion might help. It provides step by step instructions on most commonly used email programs.

how to set up my email ?

If all your settings are correct, there might be an outage currently.