Same issue here. Haven't been able to log in with my Nintendo Switch for 2-3 weeks now.
v1.16.210
Failed to login
We could not sign you into your Microsoft Account. Access to Realms, Profiles, and your Marketplace items will be limited. Please try again later.
Error code: Creeper
Same issue here. Haven't been able to log in with my Nintendo Switch for 2-3 weeks now.
v1.16.210
Failed to login