Getting HTTP 500 error when using custom OpenID auth provider

Question

I've added a custom OpenID authentication provider for my Azure function app. I've entered the issuer URL, authorization URL and token URL.

When I try to access my http function, it redirects me to the auth provider login website where I enter the credentials and it redirects back to the callback URL with the auth code in the query parameters.

But it seems it is not able to complete the authorization process and returns an HTTP 500 error. See screenshot below.

• I'm not able to see the realtime auth logs anywhere. Please suggest if that is possible somehow. Then I can get to the actual issue we have here.
• What could be the issue here? Please suggest a possible resolution.