I attempted a front axle outer boot replacement on my Ford Focus Mk1 by disassembling the outer CV joint, replacing the rubber boot, and then reassembling. I backed the car out of the garage, but then the drive to the wheels disengaged. I heard a light grating noise, but got no forward or reverse drive. During fitting, I rotated the axle several times while replacing the rubber boot, the other wheel remaining on the ground. Did I damaged something - or perhaps pulled the inner joint out from the transmission?
I would bet the issue is you haven't engaged the inner CVJ into the transmission fully. You may or may not be able to check it without disassembly, but there's a chance you might. If you see any leakage at where it interfaces at the transmission, you know for sure you have an issue. You might be able to use a brass drive and hammer it home, if not, you'll have to take it apart and see if there is any wear at the tip of the splines for the inner side. The differential being open will allow it the differential to spin if one side isn't able to apply power.