I came across the same issue and finally resolved it by adding fixed height for the custom keyboard in its viewWillAppear method by adding a height constraint directly to the keyboard view. override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) let desiredHeight: CGFloat = 250 // Set a default height // Remove any existing height constraint to avoid conflicts view.constraints.forEach { constraint in if constraint.firstAttribute == .height { view.removeConstraint(constraint) } } let heightConstraint = NSLayoutConstraint( item: view!, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: desiredHeight ) view.addConstraint(heightConstraint) } This code snippet removes any existing height constraint on the keyboard view before adding the new height constraint. It sets a fixed height (desiredHeight) for the keyboard view when it appears. Hope this helps.