You may need to attach a Lens Gear to your lens.
You may view the user’s manual video below for an instructional on how to secure a Lens Gear to your lens.
A Lens Gear is used in order to determine the exact location of your macro, it behaves like a hard stop.
Important: Please be sure that your camera is fully tightened on the Head Module’s L-Bracket, then while compressing the Focus Module towards your lens, tighten the screw for the Focus Lens.
Doing so, you can obtain a secure connection between your lens and Focus Module. When the Lens Gear hits the Focus Module, Focus Module will not lose contact. This hit will not damage any component of your system.