You are using https from the curl command line (secure), but you are using port 80, no TLS from HTTPCMD (non-secure). I'm going to guess that if you use http (not https) from the curl command line (non-secure), you will get the same/similar error as HTTPCMD.
You need to use TLS from HTTPCMD (see checkbox).
Also, I don't believe you need to include the "https://" portion in the request, since that is implied by using TLS checkbox.