Loop cut not working on my blender project? friends, I'm confused with my problem. is there anyone who can fix my project?
I want to do vertical edge like in a photo.

my project:https://drive.google.com/open?id=1vgpIo6qGXz5TJQUaBbO2Pn6IEMUJxGot
Press Z to see your object by transparency, you'll see an inner face, you can't create any vertical edge loop because of this inner face: with this kind of topology Blender can't guess what face the edge is supposed to go through. So just select and delete it.