problem in my machine lathe TMC250

good morning
i bought a lathe machine huron TMC 250 about three years ago 2014 , now i

have a probleme with the turret of the lathe cnc stop rotating , when i push the button to change the

tool it doesn't respond it make a sound that it trys to change the tool but it doesn't spinning.

so i hope can any body tells me what's wrong with my machine and what can i do to solve this problem.

waiting for your replay.