If that’s the home switch at the top of the Z axis travel, then the controller will refuse to move the platform higher. In that case, you should be able to move the platform lower.
The switch may have an LED indicator inside to show it’s triggered, like the one shown in this post:
Lowering the platform should turn that light off and the controller “diagnosis” screen should show the Z- switch is inactive.
With the switch inactive, you should be able to raise the platform to that limit.
If the switch stays active no matter where the platform is, it may be stuck or defective, depending on whether you find anything jammed in (or on) it.