I have discovered that you must get a receipt or your order will not clear from the app, and the next time you want to use the app, you can't because the previous order wasn't cleared. My temporary work-around is to place an order for a different location and be sure to get a receipt when you do. It took me a long time to figure out the problem and how to fix it. McDonald's needs to fix this flaw. Since I've been insisting on a receipt, I've not had any additional problems.