Push notifications not allowed
In most cases, you didn’t give the OK app permission for "push notifications". Please verify your permission in your settings and turn the ‘push notifications’ on.
OK request not submitted
It may also be that the cashier simply did not submit the OK request via the checkout. It’s essential the cashier submits the OK request in the checkout system.
If an OK request does not arrive directly, you can see this in your Timeline. To get there, go to the upper left corner in the OK app. Usually an open-ended OK request is at the top of the list, but sometimes a refresh of the list is required.