Turn the door so.
Plane hinge side of door.
A hinge can often work loose binding the door against the frame.
Test each screw by tightening it with a screwdriver.
But frequently the solution is on the hinge side.
People usually try to plane off the edge.
Use a pencil to mark this area on the side of the door not on the edge.
Hold a belt sander plane or power plane at about a 45 degree angle to the edge of the door and remove material to the witness line.
Running the plane in this direction will create smooth cuts instead of chunky bumpy cuts.
On many doors the grain runs from top to bottom instead of side to side.
That may be difficult on older painted doors.
Complete one pass per stroke with a hand or power planer with.
Plane the hinge or lock sides of the door in the same direction as the wood grain applying light pressure to remove very small amounts of wood at a time.
Run a piece of thin cardboard or folded paper in between the door and the jamb to identify the start and end point for the area that needs to be planed.
Step 2 use your ruler to measure 1 8 inch from the jamb to the start and end points on the door.
The radius of the mortise is determined.
Immobilize it with a doorstop and plane it in place see step 3.