Code Auth Flow with PKCE 401 Error

I am using the oidc-client library to abstract a lot of the tougher stuff, but am still getting a 401 unauthorized error when I try to exchange my authorization_code for an access_token.

It looks like everything is being sent correctly to the oauth/token endpoint, which leads me to believe that the problem is in my configuration with Auth0.

On that side, I have it set up for a SPA with an allowed web origin and an allowed callback url. In addition, authorization code flow is enabled.

Any help is appreciated and I’m happy to elaborate further if need be!

update: I noticed I get a token back if I set the App to “Native”, but it is also not a JWT and comes back as invalid when I try to validate it at this google endpoint$ACCESS_TOKEN