SmartThings Motion Sensor unable to pair

Here is the strange thing. I already have two of these and they paired instantly. This new one which I received today, goes completely unrecognized. Even after multiple resets. Perhaps my unit is faulty? Is there a way to run Zigbee discovery from the command line for testing purposes? How can I troubleshoot this?

Here are some additional pointers for pairing the SmartThings sensors: https://github.com/mozilla-iot/wiki/wiki/Pairing-SmartThings-sensors

Cool, thanks. I will try some of these things after I get home from work. I did read through them and the LED is definitely not flashing blue. Being color blind, I cannot tell if it is green or yellow or whatever, but I can see blue and it is not blue.

None of those solutions worked. Also the motion sensor does not have a blue light at all. It is either red or green. The only way I finally got it to pair was to remove all the other motion sensors from the Gateway, then I repaired them all at the same time. The Gateway then saw all including the new one.

I am guessing the Gateway was somehow confused and thought the new one was actually one that was already paired. I dunno. What do you guys think?