OpenNebula

If the port in which the econe-server is listening (8443) is different from the default one when using an SSL proxy.

export EC2_URL=https://mycloud.entrypoint.org:8443/

Workaround
Try changing this line in the server code:

system-wide installation: /usr/lib/one/ruby/cloud/econe/EC2QueryServer.rb
self-contained installation: $ONE_LOCATION/lib/ruby/cloud/econe/EC2QueryServer.rb

@@ -71,7 +71,7 @@ class EC2QueryServer < CloudServer

        econe_port = @config[:port]

-        params.merge!({:econe_host => econe_host, :econe_port => econe_port})
+        params.merge!({:econe_host => econe_host, :econe_port => 8443})
        super(env, params)
    end

And the following econe-server configuration (econe.conf). Remember to
restart the service after these changes:

# Host and port where econe server will run
:server: localhost
:port: your_local_port

# SSL proxy that serves the API (set if is being used)
:ssl_server:  mycloud.entrypoint.org