If you haven't fix it yet, I just did this morning, the issue is the actuator, (this actuator has 3 mechanical movements, and one electronic plug)
the electronic is just for remote and buttons to activate it
the mechanics are :
- one is the wire that goes to the indoor handle is long as they need to go all the way to the indoor handle
- the other a metal rod (shaped to fit obviously), thats the one moved by the outdoor handle
- the third one is the one using the barrel, is connected to the actuator by a small compact spring ending on a flat metal piece, (this one fit on one of the corners of the actuator) thats the one i got misplaced and by that reason my key was not doing its job
hope it helps
by the way to remove the black plastic cover, you need to remove the rod that connect the outdoor handle so you have easier access to it to remove it
advice!!, l remove the window frame because it helped me to work on it easier, I saw this video btw