Car will not Move while the transmission is in gear, what can be causing this?

I can crank it up and put in gear, but it won't go once I press the gas. Then I lifted the hood and saw transmission fluid all over and smoke coming from where the transmission fluid cap was located. Then when I went to turn off the car, I heard a weird suction sound before the car shut off.

Is it low fluid causing the car not to go while in gear or is it the transmission shifter cable or transmission solenoid?