On the kwikset locks this looks like two little teeth that the cylinder pushes back.
Kiwiset door lock gets stuck.
This is the short version of what you should attempt to do before trying anything else if the screw is loose the key will not turn all the way and the tur.
You should first test the door latch to ensure the latch is sticking inside the door and not due to a misaligned strike plate.
Kwikset is a secure door lock industry leader innovator in home safety with keyless entry and re keying technology for residential and commercial door hardware.
This video will show you how to get your closed door open because of a latch failure.
Once you have the door handle off you can now try to open the latch manually with either a large flathead screwdriver or pair of needle nose pliers.
You can see where the cylinder entered the dead latch mechanism and pulled the latch back.
This video will show you how to get your closed door open because of a latch failure.
A sticking door latch might require some lubrication or it might be jamming against the strike plate on the door jamb.