I am trying to authenticate a "My Anime List" user using Oauth2 (following this

and here is the reply:

Edit 2:

Hard coding the code challenge/verifier to 128 times 'A' (AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA) doesn't change the behavior either:

CodePudding user response：

When you include the redirect_uri in the authorization request you also need to include it in the /token request. Maybe it't that.