Driver Door will not unlock. Tried remote and key and door latch on 2009 Buick LaCrosse

Door on drivers side, will not unlock

Asked by for the 2009 Buick LaCrosse
same issue here, had them replace latch assembly.
seems to be a common issue
2 answers
Same here. Just a little lube in the right spot should cure it, but where? Anyone have a diagram of the door lock latch handle mechanism?