message: docs/auth/troubleshooting: add section for misconfigured auth providers
diff: @@ -19,3 +19,16 @@ of all sign-in resolvers. This was a necessary security fix as well as a step
  towards providing more clarity in the configuration of the sign-in process.
  You may encounter this error if you are upgrading from a previous version, in
  which case you would need to configure a sign-in resolver as described above.
  +
  +## Auth fails with "Auth provider registered for ... is misconfigured"
  +
  +This will typically only happen during development, as in a production build the auth
  +backend will fail to start up altogether if a provider is misconfigured.
  +
  +Double check that your configuration for the provider is correct. Note that environment variables
  +such as `AUTH_OAUTH2_CLIENT_ID` must be set and will **NOT** be picked up from `.env` files.
  +You can use the `yarn backstage-cli config:print --lax` command to print your local configuration.
  +
  +The backend logs should also provide insight into why the configuration of the provider
  +fails. In working setup the backend should log something like `"Configuring provider, oauth2"`,
  +while it with otherwise log a warning like `"Skipping oauth2 auth provider, ..."`.
  