Was the machine working at the time of purchase, assuming it is a used machine?
The tool release piston assembly is at the top of the spindle. It should move down and contact the drawbar when you press the tool release button. Since it is air operated, it is possible that something is gummed up. Sorry, I've never delved any deeper into the workings since mine has always worked
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)