voice-quickstart-ios: Getting Error: EndCallAction transaction request failed: The operation couldn’t be completed. (com.apple.CallKit.error.requesttransaction error 4.)

Hello Twilio Support,

I am using TwilioVoice 2.0.4 for VoIP calling in my application. I have taken the sample code from TwilioVoiceCallKitQuickStart project. But I’m facing a random issue with it.

When callInviteReceived is called with state == cancelled, and I try to end the call, the incoming call screen from CallKit does not go away and the phone continues to ring even when the call has been disconnected by the dialer.

I’m getting the below error logged on the console:

EndCallAction transaction request failed: The operation couldn’t be completed. (com.apple.CallKit.error.requesttransaction error 4.)

I searched for the possible causes of the error and found that it comes when the UUID used in CXEndCallAction does not correspond to a known call. But if that is the case, this error should be repeated all the time, but it only happens occasionally.

Please let me know what I’m doing wrong here.

    func callInviteReceived(_ callInvite: TVOCallInvite) {
        NSLog("callInviteReceived:")
        
        print("Call Invite UUID: ", callInvite.uuid)
        if (callInvite.state == .pending) {
            NSLog("state == received")
            handleCallInviteReceived(callInvite)
        } else if (callInvite.state == .canceled) {
            NSLog("state == cancelled")
            handleCallInviteCanceled(callInvite)
        }
    }
    
    func handleCallInviteReceived(_ callInvite: TVOCallInvite) {
        
        if (self.incomingCallInvite != nil && self.incomingCallInvite?.state == .pending) {
            NSLog("Already a pending incoming call invite.");
            NSLog("  >> Ignoring call from %@", callInvite.from);
            
            showMissedCallNotification(callInvite)
            
            return;
        } else if (self.call != nil) {
            NSLog("Already an active call.");
            NSLog("  >> Ignoring call from %@", callInvite.from);
            
            showMissedCallNotification(callInvite)
            
            return;
        }
        
        self.incomingCallInvite = callInvite
        

        print("Reporting incoming call for uuid: ",callInvite.uuid)
        self.reportIncomingCall(uuid: callInvite.uuid)
    }
    
    func handleCallInviteCanceled(_ callInvite: TVOCallInvite) {
        //Perform End Call action
        performEndCallAction(uuid: callInvite.uuid)

        if !incomingCallDetailFromServer.isEmpty {
            DatabaseManager.saveMissedCallInCoreData(number: callInvite.from, missedCallDetail: incomingCallDetailFromServer)
        }
            
        else {
            DatabaseManager.saveMissedCallInCoreData(number: callInvite.from, missedCallDetail: [:])
        }
        
        //Show missed call notification
        showMissedCallNotification(callInvite)
        
        //set call invite to nil
        self.incomingCallInvite = nil
        
        //dismiss the alert for incoming call
        self.dismissIncomingCallAlertDelegate?.dismissIncomingCallAlert()
    }

  func performEndCallAction(uuid: UUID) {
        
        let endCallAction = CXEndCallAction(call: uuid)
        let transaction = CXTransaction(action: endCallAction)
        
        print("PerformingEndCallAction for uuid: ",uuid)
        callKitCallController?.request(transaction) { error in
            if let error = error {
                NSLog("EndCallAction transaction request failed: \(error.localizedDescription).")
                return
            }
            
            NSLog("EndCallAction transaction request successful")
        }
    }