That is a ghost node (unsuccessful pairing, no in, out clusters) and must be deleted. It will mess up your mesh until it is gone. You will not be able to delete it as long as the hub can ping it, which means you need to remove power to the device. Then, hit refresh and repair a few times for that device until remove button appears. Then you should be able to remove it.
Then, shutdown your hub cleanly (settings, shutdown) to red light, power off at the wall plug (not micro USB, which is fragile and can break the solder joints to the PC board), leave power off for 30 seconds, power up again, boot to green light. This is the only way to reboot the Z-Wave radio, which stays powered if power is applied to the hub.
Now try again to pair the device.
