2011 Ford Escape Liftgate won't open after replacing the actuator

I replaced the liftgate actuator on my 2011 Ford Escape. I tested it and the liftgate opened normally, so it seemed to work fine. After about two hours I went out to open it and it won’t open. The actuator seems to be activating, but to make sure, I pulled the liner back and attempted to activate the actuator manually. The liftgate remained firmly closed! Help!