"Invalid client or Invalid client credentials" with ArgoCD and Keycloak

Question

When implementing ArgoCD 2.10.0 with Keycloak according to the documentation, after entering credentials on Keycloak-side, ArgoCD would fail with error

failed to get token: oauth2: "unauthorized_client" "Invalid client or Invalid client credentials"

The logs from server pod won't say anything in detail. I also got the rbac config map in place:

  data:
    policy.csv: |
      g, ArgoCDAdmins, role:admin
    policy.default: ''
    policy.matchMode: glob
    scopes: '[groups]'

I don't even know how to debug this, or where most probably the misconfiguration should be found (on ArgoCD, or Keycloak?)

Any suggestion how to find the needle?

Answer 1

... turns out that the key for Keycloak was wrong. After setting the right key, this message was gone.