I had the same thing happen to me on my 500mw 532nm crown O-like. The switch is VERY cheap. I unsrewed it (need snap ring pliers or very thin tapered needle nose in the holes that have alot of strength because it is screwed down hard onto an o-ring for waterproofing (yeah, I wouldn't test it though).
Then you press hard on the press fit clicky and it will push out.
The issue with mine was the spring is too small (diameter) and had popped out of the metal cap (looks like a top-hat) so it could no longer make contact properly/give any spring tension for the snap action and make a solid electrical connection.
What bothered me the most was that this same EXACT clicky is in 2 of my cheapo 650nm 10 dollar cheapos from ebay.
I installed a slightly wider spring and it works as new (cheap new that is).
Also, I've seen this same issue crop up on flashlights that have that same design if you put too much pressure on it (as in battery is slightly longer so it pushes the clicky in too hard).
Sorry, don't know the names of the parts. It's a really crappy setup to carry decent current from my inspection. Going to contact O=Like and get a new tailcap or clicky sent on their dime for sure. Should not have to do this on a $300 unit. On the plus side, mine tests out at a nice 607mw

so no chance I'm sending it back.
My better flashlights don't have this kind of clicky.
This doesn't mean that yours is the same though on your unit. I don't own the one you specifically are talking about. I would however be surprized if your switch isn't just as cheaply built.