Can’t get motorhome off leveling jack

I would guess a combination of a few things. An inch and a half isn't that much space. My guess would be your tires were hot and higher psi when you set up camp. After sitting, the lower temp/psi caused your entire rig to sit lower once down off the jacks. If that's the lowest spot, that's where the weight will shift and cause the largest drop. Like another poster said, you could have jacked it up, put a board or 2 under the nearest tire and set it back down. Standard board would buy you the 1-1/2" to drive off it.