On my new Atlas I had the same problem, although I was able to dislodge it by yanking.
What I found was that it made a lot of noise when deploying, because screw threads did not seem to be lubricated.
Because those jacks are exposed to road moisture and grime they should be lubricated with a dry film lubricant and not grease.
Silicone spray will work in a pinch, but wonít last very long.
The best lubricant for this purpose is Dri-Slide, which worked very well for me.
I bought it here: