Not all doors will open up. Not even if you knock on them a thousand times. Not if you try to break them down neither if you stand in front of them waiting for the doors to open.
Sometimes you just dont have the access through a particular door, and that's okay. That door won't be the last door in your life. And once you find the door you belong to, you won't need to break it, knock on it, wait for it. It will welcome you, and damn will it feel like home.