On March 15th, 2021 my Thunderbird account stopped downloading new mail. I made many attempts to fix the problem, including uninstalling & reinstalling the latest version. I get a message "Unable to log in at server. Probably wrong configuration, username or PSW." Here is the error message: ========================================================================= An error has occurred https://zlp42869.vci.att.com/sps/authservice/authentication 2021-05-16T23:29:27Z An error occurred fulfilling the current request to https://zlp42869.vci.att.com/sps/authservice/authentication. This error was caused by an internal/unexpected error on the invoked protocol module leading to the exception displayed below. Please validate configuration of the executing protocol and environment. This is not a problem with the SPS. Stack trace ============================================================================ I didn't change anything before it happened. Does anyone know what might be going on? Thanks, Andy