Artificial Intelligence shows itself as artificial in these texts...
The two first versions appear to say basically the same thing except they don't follow the same color code. The third sum up seems to evoke how one wires an "independent volume" when several pickups are used - which wouldn't make sense here.
The diagram in the first post did show clearly how to wire a single PU to a single volume control . Artie gave the reason why the volume pot wouldn't work in such a case.
Sometimes the ground lug of a pot has a loose eyelet and the resistive track doesn't connect to it no more. It might explain what happens here if the ground connections are apparently correct (ground and bare to the right lug, right lug to housing of the pot, grounding wire from this housing to the lug of the jack in contact with the sleeve).
A rational trouble shooting would consist to check and reflow the solders, then to try another pot and/or another jack plug if needed.