How can I invoke/open BB UEM Client (market) app from my Swift coe on same iPhone?

I am in the process of (learning) writing Xcode (11.4.1) / Swift 5 and trying to open BlackBerry UEM Client App in my test code on iPhone XR. Here is the code in Swift-
The following is in the CodeViewController.swift:

The info.plist has a new addition of “LSApplicationQueriesSchemes with “UEM Client” as Item 0 in its defined Array

// --------------------------

  1. Import UIKit

  2. Import AVFoundation

  3. Import LocalAuthentication

  4. Class CodeViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

  5. .

  6. .

  7. .

  8. Override func viewDidLoad() {

  9.  Super.viewDidLoad()
    
  10. }

  11. .

  12. .

  13. .

  14. @IBAction func executeTestCase(_ sender: any) {

  15. let application = UIApplication.shared
    
  16. let uemClientPath = "UEM Client://"
    
  17. let appUrl = URL(string: uemClientPath)!
    
  18. if application.canOpenURL(appUrl) {
    
  19. application.open(appUrl, options: {:}, completionHandler: nil)
    
  20.     print(" Opened UEM Client App")
    
  21. } else {
    
  22.     print("Can't open UEM Client App on the iPhone")
    
  23. }
    
  24. .

  25. .

  26. .

  27. }

// --------------------------

The iPhone is connected to the Apple laptop. Upon compilation, the app is executed automatically on the iPhone and it crashes at line # 17 with the following –
Fatal error: Unexpectedly found nil while unwrapping an Optional value: file /Users/wamiqsattar/……/CodeViewController.swift, line 17

On line # 16, “UEM Client://”, should not have a space. However, I do not know what the client path and/or the URL should be for the (BlackBerry) UEM Client app on the iPhone Xr. Can any of you please give me a viable advice on this Xcode/Swift Coding? What I am missing or what I need to do. I am guessing the (BlackBerry) UEM Client app has to have a special “client path”. Thank you.
Regards,
Wamiq Sattar