Authservice OIDC Failing With RetrieveToken Error

Configured Authservice with the new CUSTOM AuthorizationPolicy. MeshConfig extensionProviders is using grpc - all is functioning correctly and almost perfect … however, I see the following ONLY error in the Authservice log:

[2022-01-07 18:04:13.210] [console] [trace] RetrieveToken
[2022-01-07 18:04:13.210] [console] [info] RetrieveToken: form data is invalid

Line 595 of this page indicate this maybe related to " // Extract expected state and authorization code from request" … I got below (redacted)

authservice/ at 60dadd6181bfcac88374d5f944954b35e69d9921 · istio-ecosystem/authservice · GitHub (line 595).

Below is a successful return using another redirect_Uri: Example OAuth Client

POST https:/xxxxxx/

I will truly appreciate any help to get over this hump. I’m using AKS and Okta as IdP.
Thank you