Check Valve Orings or Outer Drivetrain Orings... in case of failure of any of those orings, it will like thru gripframe/solenoid/manifold...
as someone stated before, barrel leaks is almost 90% of the time, the powertube front oring, which will blow in case of overpressurized shot, or damaged/poor lubrication.
if all these fails you can still send it to a service center, so why would you throw a fantastic marker to trash? best shooting gun on the market, as any other electropneumatic device can leak gas due to user error, you just have to learn how to avoid or solve this little "issues"
Cowboy Mc is waiting for ya!