Same thing happened to me when I first put a Little Boy dripper on my Kbox. It pushed the pin down on the kbox and it was stuck, its not spring loaded but there is a bit of give. I pryed it gently with a really small screwdriver and it released enough to read and fire again. There is a white gasket like liner between the pin and the mod body, try not to damage this, gently wiggle the pin with screwdriver, its not going to pop up or anything like that and don't tighten the tank as much when you put it back on. Worked for me and alot cheaper than buying another mod.