CURL Connection refused on my server

i am trying to do curl on my own server with a sub domain that is on my server ex ( subdomain.domain.com )
but it fails, when I do the curl :
is there any solution or hint?

test 1837×238 30 KB

curl: (7) failed to connect to localhost port 80: connection refused

You are doing crul on localhost

Yes sir, in my vm have many sobdomains, please give my solution