m.amanullah7: as you can see in the error log, its a 400 bad request error. your page is opening but it throws an error.
there are a few issues with your implementation, first of all these apis at least the callback shouldn't be under the api_prefix. it should be with the rest of music-services in profile or settings.
the errors in urls starting with API_PREFIX are handled differently from the rest of the website which is why you might be getting an unexpected error.
also see line 75 of your funkwhale api file, you are wrapping all exceptions in an api bad request error.
you should log the error there and re-raise it as an api internal server error if you want. APIBadRequest is for the client making an invalid request.
