For me working again, too. Xcode 12.1 (12A7403) macOS Catalina 10.15.7

Same here in our CI system that authenticates via fastlane: An error occurred saving your changes to the Apple database.	This problem may be a transient issue on the Apple side.	If the problem persists for more than an hour, please contact your iTunes representative. (1129) XCode Version 12.0.1 (12A7300)