Did you also install the second file on the dev’s ‘File’ page, the updated Shared Stash file?
You’d need to replace your current shared stash file with that new file in order for the mod to work properly.
It looks like he added that file two days after he posted the mod, itself.
(assuming you ARE talking about ‘NTQV-D2R-BIGSTASH’ on Nexus Mods)
OH…
And if you weren’t aware of the Shared Stash file change, be aware BEFORE you make that switch…
You will lose any items that are currently in your stash when you switch to the new file, so if you have anything in there that you want to keep, move those items out of your stash and onto your characters before switching files. Then you can put them back afterward.