Mine was the rivet, check it first. I thought it was the actuator and ordered a new one then "hello rusty broken rivet". The actuator is just flopping around in the door.
If you look at this video, the rivet he pops off with the hammer is visible before you take anything apart; just open your door and check it. If that's it, and the actuator is working, find and use appropriate nut and bolt to fasten.