Not sure what this exception means

Question

I am working a Swift homework assignment, where when I click on a button, the user text moves to the label. For some reason, it is not working. I also have this exception error here:

Exception NSException * "[<HelloWorld.ViewController 0x160b08920> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key button." 0x0000600003b2e760

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }

    @IBOutlet var textLabel: UILabel!
    
    @IBOutlet var textField: UITextField!
    
    
    @IBAction func moveText(_ sender: Any) {
        textLabel.text = textField.text
        textField.text = ""
    }
    
}