OAuth prod env always return 500 error

[saru.v.2020]

I'm trying to integrate OAuth into one of the libraries and the eBay API is always throwing a 500 error in Prod env: 

{"error_id":"temporarily_unavailable","error_description":"The authorization server is currently unable to handle the request.","http_status_code":500}

whereas in the Sandbox environment, the /authorize API is working fine aka returning the auth code back in the redirect URI, but the /token API is throwing 400 bad request error:

{"error":"invalid_request","error_description":"request is missing a required parameter or malformed."}

any inputs on how to get ahead with the above issues?

[sabbashop]

I am facing the same issue, were you able to solve this?