During my last game, the screen became unresponsive. I could not tap or drag any cards. I exited the app and my home screen functioning normally. When I open the app again this screen would not respond to a tap on the resume button. I had to close the app.
Try exiting the game and close the app (double tap the ‘Home’ button and swipe it away vertically). Then re-enter the game.
If that doesn’t work, try restarting your device or turning it off and back on I should say.