With a valid user token, an application can programmatically manage playlists, fetch user listening history, add tracks to favorites, and stream audio content according to the user's subscription permissions. Why You Need a Deezer User Token
This typically indicates that your OAuth token does not have the required permissions (scopes) for the endpoint you are calling. For example, you need the manage_library scope to modify playlists. Review the permissions you requested during the OAuth flow and adjust as needed. deezer user token