CKAccountStatusCouldNotDetermine and "Internal Error" (1/2005) when trying to connect to CloudKit

I'm trying to get the very basics of CloudKit working, but am having trouble. When I perform the following,

[[CKContainer defaultContainer] accountStatusWithCompletionHandler:^(CKAccountStatus accountStatus, NSError *error) { }];

I get account status CKAccountStatusCouldNotDetermine and a CKError with a description like

<CKError: "Internal Error" (1/2005)>

I’ve tried these things:

Using different iCloud accounts
Using different devices
Turning iCloud on / off in Settings on each device
Completely resetting my device
Deleting my provisioning profile and creating new ones, including using a new bundle ID / App ID
Turning iCloud on / off in the "Capabilities" tab of my target
Using a completely new iCloud container that was never used with iCloud Drive

Xcode thinks everything is fine. I was previously using iCloud Drive (Documents) using a similar set up and things were fine.

Am I missing something totally obvious?

Solution

It looks like the issue was using a separate .entitlements file for debug versus production builds, for whatever reason.