Backed up kitchen sink is draining to outside and down into crawl space. There is no water in the cabinet under the sink. The sink does not clear, but does eventually drain... down to crawl space (subfloor is pretty saturated) and outdoors apparently. Plunging does nothing.

Side note, a few months back we had a sump failure and after replacement of the pump, I found that the drain line from the sump is blocked. I rerouted that line and have not done anything to open it to date.

Is it possible that the same drain line from the sump pump as the kitchen sink/disposal is blocked? That said, the pump line goes out of the house and into the ground whereas the kitchen drain line goes down to crawl space and then cuts across the length of the house.

Forgive me if anything seems obvious... I am simply trying to learn and DIY it