I just tried to run caddy with a caddyfile that starts with a comment.
Doesn’t work.
Leaving comment out, does.
Took me a while to figure out, just in case anybody else is wondering.
# ––––––––––––––––––––––––––––––––––––––––––––
# some comment on the very top of Caddyfile
# ––––––––––––––––––––––––––––––––––––––––––––
... caddyfile-stuff here ...