Invalid grant on access token request
We have a process that has been working like a charm for about three years in authorizing clients. Just recently , we are getting back invalid_grant errors and "Authorization code doesn't exist or is invalid for the client".
I removed our code from the equation and just used postman to request , with the same result. I pasted the temp code within 10 seconds to postman , so it should not have expired.
This is blocking us from integrating with a new client.
Hopefully, just a silly mistake on my end.
Can I get some input/guidance here?