How to end a phone call on iOS by callkit?

I want to end a phone call by callkit api. But I get this information "com.apple.CallKit.error.requesttransaction error 4". I don't know why and what happen. By the way, the phone call is real call, not a VOIP call.

CallKit CXError.h CXErrorCodeRequestTransactionErrorUnknownCallUUID 4

Prepare, enable voip for com.apple.CallKit.error.requesttransaction error 1 & create global variable CXCallController *callController

First, I use CXCallObserver get call UUID

- (void)callObserver:(CXCallObserver *)callObserver callChanged: (CXCall *)call {
}

Followed, I use some api to end the phone and I put it in callObserver

    NSUUID *callUUID = call.UUID;
    CXEndCallAction *endaction = [[CXEndCallAction alloc] initWithCallUUID:callUUID];
    CXTransaction *transaction = [[CXTransaction alloc] initWithAction:endaction];

    [self.callController requestTransaction:transaction completion:^(NSError * _Nullable error) {
        if (error) {
            NSLog(@"EndCallAction transaction request failed: %@", [error localizedDescription]);
        } else {
            NSLog(@"EndCallAction transaction request successful");
        }
    }];

Finally, I get this. PS: The UUID is not empty.

I have referenced How to end a call in CallKit. But no use. I have no idea. Please help or try to give some ideas how to achieve this. Thanks!

You can only use CallKit to manage VoIP calls that were established by your app. You cannot manage cellular calls or VoIP calls from other apps.