Why does the display turn off when I try to reassemble?

So, I got the display today. Once I plugged in all the cables, everything works as expected except that when I attempt to place the display assembly back into position in the phone, the display turns off. It seems to correlate with how high the screen is relative to the body of the phone. When the display is positioned so that the earpiece is level with the ring/silent switch, it works fine, but when I raise it into final position (glass edge almost level with plastic edge), it turns off. Any thoughts?