Thanks for your post ! DSM6 is not compatible with my NAS. I have to stay in 5.2…
“DSM 5.2-5967 Update 1” redirects now
…/web/.well-know/acme-challenge
to /var/lib/letsencrypt/.well-known/acme-challenge directory.
That’s why my http://test.synology.me/.well-known/acme-challenge was displaying a 404 error.