Are you using the correct tooling? BT and CAT have 2 different heights that the spindle needs to be for a tool change. To change the Height, you need to go into survey, "SV" then go to the Z axis. THere will be a number listed under "Zero Offset" This number determines where the axis homes out.
This may help.
https://www.fadalcnc.com/media/pdf/S..._AC_Motor2.pdf