OAuth2 PKCE Token Exchange failed error

[aditya18m]

Hi, 

I have managed to successfully authenticate users via OAuth2 PKCE. I have added the list of test users via the developer dashboard as well.

Sometimes I get the 'token exchange failed' error, even while trying to authenticate a user who has been added to my test user list. The way I fix this is by deleting the app and making a new app on the dashboard and updating the client ID in my code. I don't want to keep doing this, is there any reason this keeps happening once in a while? Any fixes/ideas?

EDIT: I uploaded the code on my team's GitHub repository. My teammate tried cloning the repository and running the django server on his local machine. This is also throwing the 'Token Exchange Failed' error. His account is able to be authenticated on my machine, but the error shows up if my code is being run on any other machine.