I noticed that disabling and then re-enabling "Media & Apple Music" access on application's settings (one under Settings app) solves the problem (well - at least temporary).

We have MPMusicPlayerApplicationController.applicationQueuePlayer working with Catalyst, but user experience is awful. When Catalyst app calls any methods of a player, the Apple Music application launches in a background and while it is launching (takes several seconds on pretty powerful MacBook Pro with 8-core i9 CPU and 16Gb of RAM), Catalyst app is totally frozen with "rainbow wheel of death" shown... Maybe it is expected behavior from technical stand-point, but it is no way desirable from user experience stand point! Any comments, Apple? Thank you!

For me this started happening on Wednesday, Jan 13th. App Connect started rejecting build upload stating value for key 'com.apple.developer.healthkit.access' cannot be '[ ]'. Some suggested that it helped to remove that key from Entitlement file completely, and then it led to App Connect rejection with email stating: ITMS-90000: This bundle is invalid - $message. The only option to select under Health Kit capability in Xcode is "Clinical records" (which my app does not need). If I completely remove Health Kit capability from Entitlements - I still get rejection with: ITMS-90000: This bundle is invalid - $message. This bundle was working just fine until Jan 13th US EST Afternoon... Apple - please help!

Nevermind. For some reason app got removed from being "iCloud app" on a phone (was no longer shown under iCloud apps on settings). Don't know why this actually happened - reinstalling app multiple times didn't help. What helped was - restarting the phone...