ATT.net won't pull up login and/or e-mail - keeps trying to load, redirects...inconsistent results

I need help with a att.net problem please.

When I go to att.net, the page commonly takes so long to load that it eventually times out. If it does come up, I click on the e-mail link and it goes on to take forever to load again. Sometimes a page will come up, but it's been redirected to the att.com page.  When that happens I can sometimes get lucky by loggin in and while that takes forever to open, i open another tab, which shows me as logged in.  Then, I can click on the e-mail or login link, which lets me into my e-mails - but not always.

This has been going on for months on 4 different computers both at home and work with different operating systems, on several browsers - for both myself and my son. Page loading is not a problem with other websites.  Our main browser is  Firefox, and we use AdBlocker Ultimate, and AdBlocker Plus with Webroot as our anti-virus program. Other e-mail programs like gmail work fine.

We are about ready to dump att.net and switch all our accounts over to gmail.  Anybody have any ideas on what the problem is and/or how to fix it?

Thank You!!!