When searching devices from a phone directly, it will ask for pin code.
In this way, the device can't be successfully connected.
Normally, to connect with iGS618,you need to open iGPSPORT app firstly.
In this way, you will search the device iGS618 in iGPSPORT APP and there will be no such request for pin code .
A guide video for connecting with APP for your reference.