App in TestFlight cannot connect to iCloud (CloudKit) running in Europe, but can if run in US/Canada

I am testing app - it is delivered via TestFlight. Same version cannot connect to iCloud Services (CloudKit) if it is running in Europe (Spain), but works just fine if run in US or Canada. Anyone has any suggestions why this might be happening? iOS Device (iPad 8th gen with latest iOS) in Europe is connected to iCloud and iCloud is enabled for the app installed on a device. Error I am getting is: CKErrorDomain error 4
App in TestFlight cannot connect to iCloud (CloudKit) running in Europe, but can if run in US/Canada
 
 
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