MusicKit web 403 error when authorizing

Hello,

I am working on the Musickit web browser application. I have created my developer token as mentioned in the documentation.

When I call the authorize() method to authenticate, I get the Apple Music pop up as expected. However, after entering the user credentials and "allowing" access, I get the following error: POST https://play.itunes.apple.com/WebObjects/MZPlay.woa/wa/webPlayerLogout 403 (Forbidden)

musickit.js:28 Uncaught (in promise) AUTHORIZATION_ERROR: Unauthorized at https://js-cdn.music.apple.com/musickit/v3/musickit.js:28:269512 at Generator.next (<anonymous>) at asyncGeneratorStep$u (https://js-cdn.music.apple.com/musickit/v3/musickit.js:28:266594) at _next (https://js-cdn.music.apple.com/musickit/v3/musickit.js:28:266821)

I am using an user account with paid subscription to Apple Music. With the JWT created, I am able to make API calls and receive the response for requests that do that need the userToken.

I am currently stuck at this step and would like some help to root cause this issue.