Cannot re-establish account after changing password

I have an AT&T email account which was working perfect in Windows Live Mail 2011 until I changed my password. Now, it keeps giving me this error message:
Unable to send or receive messages for the Att (ssimmons53) account. An incorrect password was entered. The next time you send or receive messages, you'll be asked to enter your user name and password for this account.

Server Error: 0x800CCC90
Server Response: -ERR [AUTH] invalid user/password
Server: 'pop.att.yahoo.com'
Windows Live Mail Error ID: 0x800CCC92
Protocol: POP3
Port: 995
Secure(SSL): Yes

I followed ALL the instructions on Windows Live support site, changed everything, deleted the account, re-established it, and rebooted the computer. I called Microsoft and they said they could not offer any other help other then what is on their website and provided me with the same link I had already used. How can I get this to work like it was once before??????