Thread 1: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value

func setUpProviderLoginView() {

         let button = ASAuthorizationAppleIDButton(authorizationButtonType: .signUp, authorizationButtonStyle: .black)

         button.addTarget(self, action: #selector(handleAuthorizationAppleIDButtonPress), for: .touchUpInside) 

         buttonSignUpStackView.addArrangedSubview(button)  // Getting Error Here

}

Are you sure that your buttonSignUpStackView is not nil?

Beyond that suggestion, we would need to see more of your code to better diagnose the problem.

So buttonSignUpStack is an outlet from my storyboard and it already contains some views so I wouldn't think that it is nil. Does it have something to do with programmatically adding this button to a stack i created using storyboard?

Like I said, we'd need to see more of your code to properly diagnose the issue. Can you post the code for your ViewController?