Z-axis only moving upwards

Vertex 3D Printer Vertex - Assembly and user manual
1

I was trying to calibrate my Z-axis, but no matter if I had the plastic stopper thing with the spring on it further up or further down, the plate only moved upwards until it was pressing against the nozzle (and trying to move even more upwards).

Any suggestions on how to fix this?

2

An to add to this, the first time I pressed autohome it kind of worked, then it stopped before the nozzle, but all attempts after that has just moved everything upwards…

3

Check the end stop for the Z axis.
Since it is optical you may need to clean it with a soft cloth.