CKContainer.discoverAllIdentities always fails

Question

The CKContainer.discoverAllIdentities request always fails in my CloudKit app. It has continually failed over the course of several days.

A simplified versi

Answer 1

Just another data point on this that might help with the overall picture. I was still seeing this error on 11.2.5 when I used my own iCloud AppleID (with hundreds of contacts) while running a Test App that called discoverAllIdentitiesWithCompletionHandler. I'd get the dreaded CKError 0x1c0051730: "Server Rejected Request" (15/2000); server message = "Internal server error". When I switched to run the exact same code on my daughters iOS11.2.5 device (with just a handful of contacts) the code worked fine. Leads me to believe there is some rate limiting going on when there are a lot of contacts with iOS11. (P.S. No errors at all running on iOS10)