Hello @rich3355,
I can understand how concerning it is to be getting those error messages when you try to log into your myAT&T account. It will be my pleasure to help!
One step is to clear the browser’s cache and cookies? If not, please clear them and then close all the windows, before trying again. Another step is to try accessing your account on a different browser to see if the same error pops up.
Please let me know if these steps work! Have a wonderful day!
Katie, AT&T Community Specialist