Don't quote me on it (I don't even have a 3d printer yet! ), but if i remember correctly, if the steppers are "turned off" the gantry will "drop down" (i think the person working on the D3D PCB Mill had some issues with this?
Probably some sort of Gcode issue where there needs to be some line on "keep the holding force in the steppers live once the program ends" ?
Also are you in the OSE Discord Channel yet? If not we can probably do some "rapid troubleshooting". I don't know who all has D3Ds on there, i think GoldFishLaser does? Either way should help speed this process up?
Excited to see what all you can do with the printer once it "gets going" either way, best of luck!