sbcglobal.net email is suddenly not bringing emails into Outlook

Yesterday, my Outlook account suddenly stopped receiving emails from sbcglobal.net, in the ATT network. It receives emails from gmail to Outlook perfectly. We have tried getting a new secure mail key and replacing the previous one, checking all incoming and outgoing POP server settings, "repairing" Outlook, rebooting our router, restarting the computer, restarting Outlook. The Outlook says "send and receive error" or  "reported error 0x80042110 ...inconsistent information ... number of messages returned by the STAT command does not match the number of items returned by the UIDL or LIST commands..."

I'm on Windows 11 with Microsoft Outlook or Microsoft 365 MSO (Version 2309 Build 16.0.16827.20014) 64-bit

I could really use some help!