I cannot access Microsoft Teams using any channel

Question

Error after login (taken from Console logs):

{"graphQLErrors":[{"message":"Cannot return null for non-nullable field AuthenticationUserProfile.upn.","locations":[],"path":["authenticationUsers",0,"profile","upn"]}],"clientErrors":[],"networkError":null,"message":"Cannot return null for non-nullable field AuthenticationUserProfile.upn.","originSlotName":"main","originAppId":"com.microsoft.teams.integrated-auth"}
error @ v2/:6

I understand I need to setup/fix an org somewhere for my account, but where when I cannot access this service at all?