Show ViewController Error - ios

Question

I am trying to show my "ProtectedViewController".
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let controller: UIViewController = storyboard.instantiateViewController(withIdentifier: "Protected") as! ProtectedPageViewController
self.present(controller, animated: true, completion: nil)
When i try to display it error pops on the step
self.present(controller, animated: true, completion: nil)
as on Screenshot below:
Code below isn't working too:
let pvc = ProtectedPageViewController()
self.present(pvc, animated: true, completion: nil)
The same error.Have tried everything.
Error from stack trace:
*** First throw call stack:
(
0 CoreFoundation 0x0000000108a2c34b __exceptionPreprocess + 171
1 libobjc.A.dylib 0x000000010807021e objc_exception_throw + 48
2 CoreFoundation 0x0000000108a30442 +[NSException raise:format:arguments:] + 98
3 Foundation 0x0000000107c06edd -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 195
4 UIKit 0x0000000109be1942 -[UIKeyboardTaskQueue waitUntilAllTasksAreFinished] + 165
5 UIKit 0x000000010934ec14 -[UIKeyboardImpl setDelegate:force:] + 1404
6 UIKit 0x0000000109776152 -[UIPeripheralHost(UIKitInternal) _reloadInputViewsForResponder:] + 981
7 UIKit 0x000000010977f95c -[UIPeripheralHost(UIKitInternal) _preserveInputViewsWithId:animated:reset:] + 498
8 UIKit 0x00000001092409b7 -[UIViewController _presentViewController:modalSourceViewController:presentationController:animationController:interactionController:completion:] + 1178
9 UIKit 0x0000000109242702 -[UIViewController _presentViewController:withAnimationController:completion:] + 4971
10 UIKit 0x00000001092456df -[UIViewController _performCoordinatedPresentOrDismiss:animated:] + 530
11 UIKit 0x00000001092451c5 -[UIViewController presentViewController:animated:completion:] + 179
12 Registration 0x0000000107a7208a _TFFC12Registration23LoginPageViewController17loginButtonTappedFPs9AnyObject_T_U_FTGSqV10Foundation4Data_GSqCSo11URLResponse_GSqPs5Error___T_ + 3482
13 Registration 0x0000000107a695fb _TTRXFo_oGSqV10Foundation4Data_oGSqCSo11URLResponse_oGSqPs5Error____XFdCb_dGSqCSo6NSData_dGSqS1__dGSqCSo7NSError___ + 203
14 CFNetwork 0x000000010b8756b0 __75-[__NSURLSessionLocal taskForClass:request:uploadFile:bodyData:completion:]_block_invoke + 19
15 CFNetwork 0x000000010b874f5c __49-[__NSCFLocalSessionTask _task_onqueue_didFinish]_block_invoke + 308
16 Foundation 0x0000000107b742cd __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 7
17 Foundation 0x0000000107b73faf -[NSBlockOperation main] + 101
18 Foundation 0x0000000107b726ac -[__NSOperationInternal _start:] + 672
19 Foundation 0x0000000107b6e5ef __NSOQSchedule_f + 201
20 libdispatch.dylib 0x000000010c2600cd _dispatch_client_callout + 8
21 libdispatch.dylib 0x000000010c23de6b _dispatch_queue_serial_drain + 236
22 libdispatch.dylib 0x000000010c23eb9f _dispatch_queue_invoke + 1073
23 libdispatch.dylib 0x000000010c2413b7 _dispatch_root_queue_drain + 720
24 libdispatch.dylib 0x000000010c24108b _dispatch_worker_thread3 + 123
25 libsystem_pthread.dylib 0x000000010c60a712 _pthread_wqthread + 1299
26 libsystem_pthread.dylib 0x000000010c60a1ed start_wqthread + 13
)
libc++abi.dylib: terminating with uncaught exception of type NSException
Please help me to find the way to fix it.
Thanks in advance!!!
P.S.: Using iOS 10.0 and Swift 3

Answer 1

The stacktrace shows something in NSURLSession context. Are you presenting the ViewController from within the main thread, or from some worker thread?
Please check if executing your presentation call from the main thread succeeds:
DispatchQueue.main.async {
// here your presentation call, e.g.
self.present(controller, animated: true, completion: nil)
}
If not, you should post the complete exception (from the output window) and/or a little more code (more of the area you present the controller)