Can't trim or divide "entity"

I am trying to clean up the lines around this closet on my floor plan I am drawing but somehow I did something weird when I created it and It is not letting me. When I try to trim the vertical line on the top left and when I try to divide the other line on the right so I can cut out the snippet where they intersect, it just keeps saying "Cutting point is not on entity". dxf file attached.
Thanks!

house_1st_floor.dxf

You can't trim that protruding bit of a line at the top left because it is part of the dimension. Make Extension lines - Enlarge smaller or move the dimension.
I have no problem dividing the vertical line on the right. Maybe your snap settings are not appropriate. Or your procedure is not right. LibreCAD asks you for the next steps, watch at the bottom and at the command line.