My tiled shower leaks and we have narrowed it down to the drain flange where the tile set. Can I fix this by using a resin or epoxy instead of grout?

My tiled shower leaks and we have narrowed it down to the drain flange where the tile set. Can I fix this by using a resin or epoxy instead of grout?

THere should be a membrain below the shower pan... the grout on the tile isn't what makes it leak proof.