There is a process to this mod.
First, with the top cap removed, loosen the connector pin as far as it will go without falling out and then attach your topper.
Next, tighten the connector pin until it's snug.
Then install the battery tubes.
Next, take the button, press the black ring down, and tighten the pin until it's nice and snug.
Insert your battery.
Finally screw the button into the bottom of the mod.
If the pins are loose the mod doesn't work right.