Thread 1: breakpoint 1.1 2.1

How do I solve?

This is my code:

import UIKit

class ViewController: UIViewController {

  var flipCount = 0 {
    didSet {
      flipCountLabel.text = "Flips: \(flipCount)"
    }
  }
   
   
  @IBOutlet weak var flipCountLabel: UILabel!
   
// in this area appears the Thread 1: breakpoint 1.1 2.1 (in the line of "flipCount += 1")

  @IBAction func touchCard( sender: UIButton) {
    flipCount += 1
    flipCard(withEmoji: "👻", on: sender)
  }
   
   
  @IBAction func touchSecondCard( sender: UIButton) {
    flipCount += 1
    flipCard(withEmoji: "🎃", on: sender)
  }
   
  func flipCard(withEmoji emoji: String, on button: UIButton) {
    if button.currentTitle == emoji {
      button.setTitle("", for: UIControl.State.normal)
      button.backgroundColor = colorLiteral(red: 1, green: 0.5763723254, blue: 0, alpha: 1)
    } else {
      button.setTitle(emoji, for: UIControl.State.normal)
      button.backgroundColor = colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
    }
  }
}