Latest release is a fabric based mod, as posted on CurseForge. This may be a known change if so please advise if not please update with forge version of the mod.

VanillaDeathChest 1.15.2-1.10.3.9-Fabric
Apr 19, 2020

This should be fixed very shortly tomorrow.

I may have to make a separate project for the Fabric version to avoid this issue.