I have an exterior door that is stuck to an extreme. I tried a tip from TOH which is to put shims behind the hinges. After that did not work I decided to peel off the door casing for a better look. I found that the jamb sides and door are level, but the top of the jamb is way off level. The door gaps between the jamb at the upper right and lower left, and as a side effect pushes the door into the bottom right jamb/ floor, causing the sticking.
Any advice as to my best move forward? Thanks!