Trailer hitch receiver help needed

[nctalkinghead]

I was removing the receiver from the car and could not get it to latch in the RED position before it fell out. So it is now stuck in the GREEN position and will not go to RED nor will it go back into the car!

When I try to move it from green to red it moves part way but never far enough to lock in the RED position.

Any ideas from you veteran hitchers for this guy trying to use this thing for the second time

thanks

 

[EA500]

The red knob needs to be pulled out and rotated. If you only rotate it only goes half way.