cURL command to my API returns couldnt resolve host

[#1]

Hi I follow the tutorial for generating an API proxy

I just used the Persons API spec.

giving me a proxy at http://myname-trial-test.apigee.net/persons

issuing a curl command like

curl http://myname-trial-test.apigee.net/persons

gives error "Couldn't resolve host '.....

Do I need to open up a firewall or something ?!