In Bypass you can take advantage of Offline Mode to keep the lines moving even if your network fails you. Naturally, this comes with some risk. Setting your Offline Credit Card Amount Limit can help minimize the amount of risk you are willing to accept.
To adjust this amount navigate to Configuration > General Settings and scroll down to the Payments section. Any transaction that has a total more than the amount in this field will get declined when the register is working in offline mode. If this amount is not filled in then all credit cards will be declined while working in Offline Mode.