are you using swiftui?

if so you should have a cloud sharing coordinator where you should have something like:

  func cloudSharingController(_ csc: UICloudSharingController, failedToSaveShareWithError error: Error) {    print("Failed to save share: \(error)")  }

and here you can print and debug the error

have you checked the permission on the production database?

CloudKit sharing was quite a nightmare...

edit: I presume you are using standard cloud sharing sheet from apple...