App looks good, shows offers, but not accepted by stores

The app is nice looking, updates with good offers frequently, like the punchcard for the beverages, extra offers when local team wins, but thats the extent of the usage of the app. I have not been able to use a single offer or coupon at a McDonald store.
The cashiers either dont know to use it or most times the coupon code is not accepted by their system nor is the bar code accepted. In the end I pay full price and dont get any offers. Due to this it is absolutely useless.
Love using the Dunkin Donuts app or even Taco Bell, Panera Bread, etc. Someone needs to rethink this app in conjunction with the system being used at the McDonald locations.

ItsAmit about McDonald's