Oauth Connection

We had an active Zoom server-to-server oauth app that was working and at around August this last year it suddenly decided to stop working. I've come to the point that I can't figure it out on my own and I need to get some help from one of your engineers to help me troubleshoot.

What is happening is that, on my Oauth application, I am making a token request and *successfully* getting back an `access_token`. I then immediately go to use that token and get an invalid token response.

The most confusing part about this, again, is that this server-to-server app was successfully accepting API; however late last year it decided to not accept my freshly generated tokens.