For me setPositionTarget() works.
- with move_group->getEndEffectorLink() check if your end-effector is correct.
(or you can just pass your end-effector name as string as a 4th argument)
- make sure the position you pass into getEndEffectoLink() is reachable with this end-effector. The values you used would not be reachable for my robot (Neuronics katana), but it depends on your robot.