If a sensor monitoring entry is left in the open position, the system cannot arm this sensor. You can either close the sensor and then arm your home or continue arming your home with the sensor open. If you choose to continue arming with the sensor open, the app will give you the option to bypass the open sensor(s). If you select yes, then the other sensors in your home will arm, and that sensor will remain disarmed.
To bypass means to keep out of being armed. This method is only applicable for a Motion + Entry sensor.