I cannot get my att.net email to load

I have checked my email settings with att today and they are correct but my mail will still not downoad.This problem occures sporatically, but has always seemed to resolve itself, except today.

Cathy, I wonder if there are issues with the ATT server? I just migrated to eM Client yesterday from Thunderbird as I was having intermittent problems downloading email from my att.net (that wasn’t the only Thunderbird issue). I assumed the problem was Thunderbird POP 3 but perhaps the problem is ATT. I assumed the problem was Thunderbird as I could always check email by going directly to Yahoo.com and see incoming email there. Never a problem with seeing current email by logging into Yahoo.com. In setting up eM yesterday I eventually got to where I could send email but I have not been able to download any email into eM from the att.net POP 3 server. I also double checked my settings against att.net recommended POP 3 settings. I started a separate conversation on that yesterday.  

I cannot load att email. It loads OK on my iPhone and I can login on Yahoo. How do I load?