See attachment. The micro-usb connector in the holder is about 4.5mm high, but my Nexus One will only slide over it like for 2mm and then it feels like it is blocked by something. I've used force, but no movement whatsoever.
I find it strange too.. I don't see anything odd on the connector, nor on the female connector on my Nexus One. I guess I'll take it back to the store...
Google Nexus One!