Since a couple days ago, CloudKit database queries in my app and on the CloudKit dashboard fail with the error "request failed with http status code 500". Nothing significant changed in the app recently, and it has otherwise worked well most of the time for more than a year, although CloudKit seems to have outages somewhat frequently. My app is mostly unusable without access to the CloudKit database, so this is a critical issue.
I have also filed a Feedback report (FB13709321) on this issue.
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.