Sorry, I forgot to follow up on this: For whatever reason, after about a day, it started working on Mac too.

After about a week, the "http status code 500" errors stopped occurring, and my app started working again. I didn't make any changes during this time. It appears to be a problem with the CloudKit servers. However, it's unnerving to me that my app was not functional for a week, and I got no response on this forum, through the Feedback Assistant, or to my request for a code review.

Feedback number: FB13709321 Based on the response I received today to my request for technical support, it seems that there are some ongoing problems with CloudKit that Apple is investigating.

No, this is not related to the "Quota exceeded" errors. I am aware of those and already handle them, since many people don't have enough iCloud storage and my app uses a large amount of storage. The problem I'm discussing here is the "status 500" errors that occurred for about a week and rendered my app useless, and then suddenly stopped happening. And now there is a different problem: CloudKit notifications are not being received by my app. These have always worked before and suddenly stopped working around the same time as the "status 500" errors. I'm still waiting for a resolution of this problem, which has disabled an important feature that my users rely on.

I am in the same situation: The new version of my app was released with a paywall, but the in-app purchases are stuck in "Waiting for review", so there are no options for the user to select. Apple, please fix App Store Connect. It causes so much needless pain for developers building on your platforms.

In fact, I can add an app group identifier that doesn't start with group. only if my app's destination is macOS only. Then, when I add iOS as a destination, Xcode shows me an error that says that app groups must begin with group., and the app won't build. This seems to be a serious bug with Xcode. There should be separate app group sections in the "Signing & Capabilities" panel for macOS and iOS to allow for these different conventions. I've also noticed that the permission prompt is shown every time the app launches, even after the user has given their permission on the first launch.

As a temporary workaround, it looks like you can add the app group ID prefixed with the team ID in your .entitlements file, and the macOS app will build and use the correct app group directory without asking the user for permission. Then, to allow your iOS app to build, you'll need to remove the macOS app group ID from that file. I haven't tried submitting to the App Store with this setup yet, but assuming it works, you'll need to remember to include the correct app group ID for each build you submit. Since Apple is unlikely to change their access control policy for app group directories on macOS, the most sensible solution would be to create a separate app group section for macOS under "Signing & Capabilities" in Xcode, which allows you to specify the correct app group ID for macOS.

I have a similar problem that I posted about here: https://developer.apple.com/forums/thread/763826

See also this post about the same issue: https://developer.apple.com/forums/thread/762639 As that post mentions, this problem could also be solved if the macOS provisioning profile included the app group identifier used in the iOS version.

I understand, that the security alert should actually not be shown and is currently only shown for XCode and TestFlight builds. I can verify, that no such alert is shown when I run the App Store version of my app. I just tested this myself and can confirm that it is the case. So I'll keep using the app group prefixed with group. in my macOS app, and hopefully this will be resolved for Xcode builds from macOS 15.1 on.

I'm having the same issue.

I'm running iOS 18.0 on my iPhone 16 Pro, and using Xcode 16.1 beta 2 as suggested by @nekno worked for me.

I'm having this same problem: Scrolling on macOS with the scroll bar is smooth, and very smooth on iOS, but jittery when scrolling with the trackpad or mouse scroll wheel on macOS.

Is there any chance that this just gets fixed in Xcode so that I can use an app group starting with "group." in a multi-platform app without getting the permission popup every time I run my app from Xcode?

None of the suggestions on that page helps. These are my code signing settings, which have never changed.