Sims Can't Interact with Objects
It sounds like you have a routing error. It could be a mod or CC causing it, but routing errors will happen in a vanilla game. If the sim is in a room, put the walls all the way up and go to build mode and click on the doors to the room to make sure they are place properly. Sometimes, they will glitch and you can see the frame but not the door itself.
Overhead objects like hanging light fixtures and pot racks will block a route too so, especially when you play in a house with the short walls so you should check for that and remove, relocate or change those if you find any.
If not either of those, then have you placed anything with MOO? Sometimes those items will block routes. I had one of the big stuffed animals that I placed with MOO next to a staircase and it blocked the stairs because it intruded into the wall next to the stair.
And if none of that works, try moving the sim out of the house and then back in (sell the furniture so it will be there when you move back in). That should clear it up at least temporarily.
Hope this helps.
