Check that the center post of your battery is making contact with the center post of the atomizer.
Pull your post. First, shut down your battery with the 5 click thing or however you do it with your unit. Take a bent paperclip or something similar and carefully work around the edge of the battery's center post, prying it up and lifting it. It's floating inside a gasket. You only need to lift it a tiny bit, maybe 1/64". If it got pushed down by a slightly out of spec atomizer connector post the next one won't make contact unless it's pulled back up.
Ideally, you can first verify that this is the problem with a multimeter to make sure the connector is getting voltage when you press the button. If it's getting voltage, then the problem is the connector and the center post is almost certainly the culprit.
If you don't have a multimeter, go ahead and pull the post anyway. It won't hurt anything. If you pull it a bit too much, the next atomizer you put in there will push it back down to where it's supposed to be.