I found a related post and I don't think it was the same problem? But, it feels like the handle is slipping and not releasing the door. It's done this before, but I could open the door with a few tugs of the handle.
I just went outside and tried to figure out the source of the problem. It may or may not be my locking mechanism. I guess that the lock isn't coming all the way unlocked and releasing the door. If anyone has an idea, please, let me know.
Stuck doors can be tough, try to get the door panel off and soak the latch assembly with penetrating oil. Hopefully notching is broken yet, getting the panel off will let you see if the rod is pulling far enough.
I had the other problem. My door would not close sometimes. Got worse and worse. Finally sprayed lots of lubricant (silicone I think) into the lock/latch mechanism and kept working it. Has worked fine for a couple of years now.
Hard to get to that location wioth the door shut though. Also very hard to get door panel off if shut.