MDX files is not found 404

my bad, I tested it, so I made a mistake with the version.
https://new-portfolio-moonies.vercel.app/en/work

for more detail
when i use direct [slug] url Protfolio With Onec UI
is still working.
i must have setting something
and i follow this example https://magic-portfolio-for-next-js-self-theta.vercel.app