Still seems to be an issue in the release candidate. Here are 2 more bug reports: FB13006620, FB12808549.

Did you manage to resolve this? Am getting the same error. Have submitted bug reports FB13006620 and FB12808549 but the issue still seems to be there in the release candidate.

You need to reach-out to Dolby I'm afraid. They wanted to see screenshots of my app when I did this.

I'd love to know the answer to this one too - such a basic requirement. I raised feedback on it months ago (FB11706965). Also you'd think that if you tried to edit a playlist that you weren't allowed to edit at least it would throw a specific member of MusicLibrary.Error which indicated what happened. But no - you get a completely generic error. The only way you can tell what happened (as far as I can see on 16.1) is by looking for a specific string in the error text (reported as FB11740727).

I’m seeing this too: the call arbitrarily blows-up when saving larger playlists. There doesn’t seem to be a specific upper limit - sometimes 3,000 tracks will fail, other times 6,000 tracks will work fine. Suspect it depends on server loads (fyi 500 is a gateway error). It wouldn’t be so bad if you could break the call up and add to a playlist chunk by chunk but the “new” MusicKit call to add to a playlist is completely unusable as it seems to map to the old (comically slow) MPMediaPlaylist.addItem method. The other interesting thing you will find is that if you read the playlist tracks immediately after creating a new playlist, there aren’t any. They come along a few seconds later. So much for async/await. Worse still, if there’s a failure between when the call apparently “succeeded” and when the tracks subsequently appear, it’s completely silent. You just end up with a playlist with no tracks. I get the impression that Apple are not eating what they cook when it comes to MusicKit. And incidentally all of the above issues have been reported by me via Feedback Assistant for months without so much as an acknowledgement.

Hi - is there any update on this please? I've just added additional details to FB11733455 as error reports are continuing to come in from users.

We are seeing this too

I'm getting this too, on 14.1 RC2. Errors flash-up in the Issue Navigator, then vanish, leaving you with a failed build and no clue as to why. These last couple of Xcode builds have been virtually unusable. Can someone at Apple PLEASE look at this urgently.

Thank you - requested details now added to FB11733455. Unfortunately I can't provide a sysdiagnose as we are unable to reproduce (it works fine in our dev & test environments). We will look in to implementing "Proactive Restore" - it looks like a much smoother process for our customers.

It’s the same app and same IAP. Catalyst allows you to do this.

Seems fixed in iPadOS 16 beta 10 (20B5056e)

Still broken in iPadOS 16 beta 9 (20B5050f)

I’ve created FB11529157 for this

I hit the exact same error (see here). By the way you might want to try adding the MusicKit tag to your post. So far for the WWDC22 enhancements to MusicKit I’m finding: Catalyst isn’t supported, period iPad is meant to be supported but doesn’t work iPhone kind-of works but good luck getting any help or support when you have questions I’m disappointed, to put it mildly.

Apologies if it's a bit obvious but probably the first thing to check is that you've actually granted permission for your app to access Apple Music on your Mac. i.e. in the System Preferences app, Security & Privacy -> Privacy -> Media & Apple Music. Is your app listed there and is access enabled? Just to confirm, this call is working Ok for me on Ventura (unlike any of the newer MusicKit functions).