NotificationBanner: Crashing all the time

Can you please explain why this library is crashing all the time to me? Here is the code to run the banner:

  func showBanner(text: String) {
    let banner = NotificationBanner(title: text, style: .info)
    banner.autoDismiss = false
    banner.applyStyling(titleFont: .custom(type: .regular, size: 14), titleColor: .white, titleTextAlign: .center)
    banner.backgroundColor = .init(red: 75, green: 75, blue: 75)
    banner.show()
  }

Here is the crash:

2020-12-17 12:46:06.465576+0100 APP[836:108657] [LayoutConstraints] Unable to simultaneously satisfy constraints.
	Probably at least one of the constraints in the following list is one you don't want. 
	Try this: 
		(1) look at each constraint and try to figure out which you don't expect; 
		(2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x28133a1c0 UIView:0x105b10580.width == - 16   (active)>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x28133a1c0 UIView:0x105b10580.width == - 16   (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKitCore/UIView.h> may also be helpful.
Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value: file NotificationBannerSwift/BaseNotificationBanner.swift, line 530
2020-12-17 12:46:08.752985+0100 APP[836:108657] Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value: file NotificationBannerSwift/BaseNotificationBanner.swift, line 530