Hm. If it was low in charge then it might run that atomizer but not the LR cartomizer. If it's blinking when you push the button while the carto's screwed in, then the battery's almost dead.
Make sure you're charging it in a KGO charger -- it'll fit an Ego charger, but it won't work. I had to use a silver Sharpie to label them, otherwise I'd get them confused. I've also found that sometimes if the battery or cable gets jostled on one of my chargers, it'll stop charging (which is highly annoying). If it still needs charging, It should blink when you screw it in and the light come on as red.