Homing problem z axis

1

have the woodworker x35 when it first boots up it ask to home machine? I click on ok and the router z axis only goes about halfway up and then it goes to left corner. so then the z only goes halfway up regardless if you use joystick or screen, but if you restart controller the joystick and screen let you go all the way up and down left and right but once you try to home it the problem is back.