We get this question from time to time and it's almost always because the connection is actually very tight, especially on the first time pairing them together.
You should feel it snap into place under a good bit of pressure. Just make sure that the logo on the adapter and base are both facing the same direction...it only goes together properly with that configuration which is necessary for the polarity. As long as everything is lined up, don't worry, you won't break anything. If done correctly, you shouldn't see any of the plastic molding.
