It looks like you have isolated the problem to the solenoid. Sure sounds like the piston is stuck. This is gonna sound crazy but if you put juice to the solenoid and tap the coil with a screwdriver handle it may free it up. If it is successful, you will hear it “click” which I will assume you are not hearing now.
Welcome to Lake Wobegon where Justin and David utilize abductive reasoning to help solve F/SS issues.
Happy Trails and Remember the Pequod.