Hi there. You can try to reset the sensor (see the first post for reset instructions), reboot the hub, bring the device within 5ft if the hub and then try to pair it.
Also check if you have any unused device handlers in your IDE that may need to be republished which may prevent the pairing from completing. Please see this topic for details: FAQ: My lock/device does not pair or appears to pair but it won't show up in the mobile app or IDE - stale DTH