On 25 October 2026, signing in to an Apple Account in the Simulator (Settings > Apple Account > Sign in Manually) fails on iOS 27.0 and iOS 26.5 runtimes (Xcode 27.1, macOS 27.0.1, Apple silicon), for a new account (SMS second factor) and for an established account (trusted-device second factor). The password and second-factor steps complete; then akd logs "Will check in with IDMS" and POST gsas.apple.com/grandslam/GsService2/postdata returns HTTP 401 with ec -22411, sec -42023 ("This action cannot be completed at this time"), followed by "Failed to check in with IDMS! ... AKAuthenticationError Code=-7026". Settings then says the account or password is incorrect. The host Mac checks in with IDMS successfully, and the account works on icloud.com. I need a second account in the Simulator to test CloudKit share acceptance. Is this a known issue, and is there a workaround? Feedback: FB25318712.