I have fixed the issue, it seems like it was a problem with the path resolution, although it should have worked in my opinion. The problem was that itch.io was not able to resolve
../
paths even if you are already one hierarchy level down your top level. I have made a dev log about it here:
https://fmproductions.itch.io/asciiventure/devlog/44192/403-errors-resolved-itch...