My @mac.com address no longer valid at appleid.com
I cannot log onto appleid.com using my @mac.com address. This has been my Apple ID for years, but with the latest version of BigSur (11.1) that address no longer works; however, @me.com and @iCloud.com still work. Is this a change to the the new software?
iMac 27″ 5K, macOS 11.1