Thank you for the response. I successfully requested authorization, and there is no more permissionDenied error. But it's still giving me the .developerTokenRequestFailed error. In the video it says all I need to do is register an AppID token on my developer portal. I did that, checked the MusicKit service box and copied Bundle ID into my Xcode project's Bundle Identifier.
2021-06-11 08:29:47.684453-0700 MusicPlayground[85583:993511] [DataRequesting] Failed retrieving MusicKit tokens: Error Domain=ICErrorDomain Code=-8200 "Media API Token Service's response was invalid (status code: Unauthorized (401))." UserInfo={NSDebugDescription=Media API Token Service's response was invalid (status code: Unauthorized (401))., NSUnderlyingError=0x600003869770 {Error Domain=AMSErrorDomain Code=301 "Invalid Status Code" UserInfo={NSLocalizedDescription=Invalid Status Code, AMSURL=https://sf-api-token-service.itunes.apple.com/apiToken?REDACTED, AMSStatusCode=401, AMSServerPayload={
status = verificationFailure;
}, NSLocalizedFailureReason=The response has an invalid status code}}}. Throwing .developerTokenRequestFailed.
2021-06-11 08:29:47.684730-0700 MusicPlayground[85583:993511] [DataRequesting] Failed retrieving tokens for MusicDataRequest.Context(url: https://api.music.apple.com/v1/catalog/us/genres). Error = .developerTokenRequestFailed.
.developerTokenRequestFailed