Problem with Pilot ACS

[Boosted]

So the problem I've been having is the gun has been simply not firing. I hear the electric click when i pull the trigger but it doesnt fire or send the bolt fired. It does this off and on and i couldnt figure out what it was. I brought it to my local gun shop and he re-soldered the connections for the solenoid thinking it was that. It works better now but after the gun stays off for a few hours and i turn it on it doesnt fire like before. Then all of a sudden it starts firing like it should. What could this be?
BTW it has a rocking e-trigger also