1. Check the pressure on the gauge to make sure the LPR isn't set too high or creeping, causing the noid to vent.
2. Make sure the screws which secure the noid to the ram housing are tight.
3. Are you absolutely certain that the leak is coming from the noid/gasket/ram housing connection? There are other possible leak sources in the back of the gun.
You may have a blown seal in the solenoid. If you're not comfortable attempting to rebuild it send the gun in to Jack.