Worm gears not working properly

We recently purchased a Cam Follower. When we put a worm gear into it, it doesn’t go all the way (it feels like the teeth don’t line up). We’ve tried multiple orientations, rotating the gear before we put it and, and nothing seems to work. Do any of you guys have experience with this and a solution?
Thanks!
(picture for reference)
cam.png

@ReeseSteindler if you bought Advanced Mechanics and Motion Kit (276-2045) then there should be two types of worms - small and large:
vex-worms-from-Advanced-Mechanics-and-Motion-Kit.jpg

Small (on the left) is the regular worm that interfaces with the worm gears and the large thing (on the right) is what they call “Lead Screw Segment” that goes into grey “Lead Screw Nut” .