Grafana SSO Error

I'm running 2.1.0 of Big Bang via a brand new installation started at 2.0.0. For some reason I have not been able to get SSO to Grafana working using OIDC Big Bang values. All other SSO is working fine including AlertManager and Prometheus.

I get redirected to keycloak correctly but after I sign in, I get redirected back to grafana but with the following error message (this is currently happening on two big bang environments that I have set up in the same way):

Grafana / Server Error login.OAuthLogin(get info from generic_oauth)

Check the Grafana server logs for the detailed error message.

Any ideas on what I can check or trouble-shoot?