Did you visit the website?
Double press and hold the middle button. Thats what I did to get mine to pair.
Plug in a USB keyboard, if you can, and that should let you get past the screen. Some ATV devices will also skip it if a CEC remote is detected.
Change batteries?
I spent an hour in Google Support Chat and just ended up replacing my google tv where I purchased it. Google tech support was unable To get it resolved.