Help for jammed screen door lock
 

Front screen door lock is jammed - can't open door. Can someone identify a screen door company they trust?

I'd try a little WD-40 or maybe some penetrating oil in the apparatus first.

You should be able to remove the mounting screws from the inside of the screen door, and then the door should open. As noted above you can try a good lubricant, I use a silicone based lube for these. Once you have the latch removed, look for broken or worn parts and if necessary buy a new latch. Take the old latch with you to make sure the holes match.