I had a problem with mine because while rebuilding the forks, I didn't realize that the nut inside on the shaft needed to be in a certain spot or range.
I set the nut wrong and had to remove the fork tops in order to reset the nut. IIRC, it's 2 something turns from the bottom. When/if you rebuilt the forks, you should be able to see the rod tip and the nut.
To be clear, the if the nut is set in the wrong position, then you screw will be too far down in the housing or maybe such that you can't turn it.
How long has it been since the forks have been rebuilt? I'm wondering if someone screwed something up, is this bike new to you?
If you set the screw all the way in, you're saying it only turns 1 time (or less) counter-clockwise?
Is the top of the screw below the housing (inset)?