Sbcglobal login credentials (password) not recognized after about 4 days

Over the past several months I have been having problems signing into my sbcglobal.net account.  I will go about 4 days being able to sign in and then I get a message that either the email address/ID or the password is incorrect.  In the login screen the email address/ID box is blank and the password is shown.  I keep entering my correct credentials until I hit the magic "too many bad tries" and have to reset my password.  I believe the system just suddenly decides my password is wrong, even though I have entered the correct password.

This started happening around four months ago.  I've gone through as many of my systems as possible to try to remove any chance of saved OLD passwords being entered automatically, but it makes no difference.  I have no explanation for why the system suddenly, routinely, decides my credentials are bad.  It is extremely frustrating!