As the title suggests, an interior door has suddenly stopped latching as it should. Previously, the door would close just fine, though perhaps you had to apply more pressure than most doors, it would latch and lock just fine. Currently, you can push it closed, but the knob is basically just a prop because you can push or pull the door open without turning the knob -- the latch just doesn't catch anymore. The major issue with this is that the door currently separates the half bath from the full bath. Strange design, I know, but basically if this door is open, you're staring at the other toilet.
Can anyone suggest a solution or explain why this change in latch function has occurred?