Probably the pogo pins aren't lined up. I had the same problem, exactly. After a while I got fed up and tried it the next day, it was fine. Screwed the box back together and it didn't work again.
It's REALLY easy to not have the pins lined up on the MB. Get your face in there, tilt it so you can see, and move the buggers so they're on there exactly. The rivets will probably help with the connection, but they'll make it more difficult to know if you're lined up properly because the holes will be smaller. My advice is to press down on the chip and try to move it across the MB. If it doesn't move and you think you're lined up, you're probably ok.