Question about Outlook Express

Please see error message below:

Unable to send or receive messages for the *** Email address is removed for privacy *** 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] (#MBR1212) Incorrect username or password.
Server: 'inbound.att.net'
Windows Live Mail Error ID: 0x800CCC92
Protocol: POP3
Port: 995
Secure(SSL): Yes

The passwords are indeed correct and have also been reset but I get the message for both inbound and outbound server.  The account, to the best of my knowledge, is not set up for the 2-step verification and the source is a trusted device (desktop) and designated as such.  I have had this issue since moving and setting up ATT U-verse but I am still able to receive and send mail on mobile devices and through Yahoo! and Outlook applications but when I try to add my account to WLM from those sites the same thing happens.  Can someone provide me with some input to try to troubleshoot?

Thanks