Approach 1: Default button on the IPC device

Press the default button and hold more than 5 seconds, the device will automatically restart, the configuration will restore to the factory settings when finished. 

Approach 2: Use iptool to restore the device

Open the iptool and search for the device, select the device and input the MAC address of the device in the lower right corner of the iptool, then click "OK" button, restart the device in 30 seconds (unplug and re-plug the power supply), then the camera will restart to set Default.