DeviceCheck for Apple Attest

Hi,

Using the https://developer.apple.com/documentation/devicecheck
I should be able to leverage the attest APIs to verify the integrity of my apps. However, I am constantly getting an unknownSystemFailure when attempting to attestKey(_:).

This is after key pair generation and clientDataHash for the challenge. Please refer to the code sample. Would appreciate any feedback on how to get this to work.

Code Block  swift
let service = DCAppAttestService.shared      
guard service.isSupported else {  
          return     
}                
service.generateKey { (keyId, error) in            
	if error != nil {                
		print("\(error!.localizedDescription)")                
		return            
	}                        
	print(keyId!)            
	let challenge = "r6ctg89rt3948tc497tn4379".data(using: .utf8)            
	let hash = Data(SHA256.hash(data: challenge!))            
	service.attestKey(keyId!, clientDataHash: hash) { (attestationObject, error) in                
		if error != nil {                    
			print("\(error!.localizedDescription)")                    				
			return                
		}                
		print(attestationObject?.debugDescription)            
	}        
}