Is it possible to use waterproof grout + sealer to fix shower room floor leaks?

I believe the leakage is at the two corners near the curb. If I pour water to two corners, there will be leakage to first floor. My guess is when the remodeler tiled the shower room floor, they broke the shower pan.

My question is if I remove all the existing grout, and apply waterproof grout, then use grout sealer to treat several times, is that enough to stop water leakage?

Thank you for your time.