There's been a few random issues with taskcluster credentials not working for all users or specific users and often times the fix is to clear those credentials (stored in local storage as
userCredentials) and to perform the taskcluster authentication again. However, it'd be better to have this happen automatically when a user logs out of the app (since this seems to be natural attempt at troubleshooting) instead of expecting users to know this process.
As :aki pointed out, ideally this would be performed on the login action in case a user is logged out automatically due to the auth0 token expiring, but this would not be worth doing until we can change the authentication flow (we currently use implicit flow and need to move to some type of authorization-code flow in order to have tokens that are valid for 24 hours instead of 2 hours). (This switch is currently blocked on whether Mozilla will be switching off of auth0 or not.)