Improve auth to fail fast with a descriptive error

Corrective action from issue #345417 (closed)

We should figure out how to improve the auth so we either fail fast with a more obvious error. As discussed in gitlab-com/gl-infra/production#5904 (comment 730006407) , we could consider a hard failure by undefining the group. We could consider setting a flag that detects that we're already attempting auth and raise an exception for any attempts to re-attempt auth.