The API Script displays error

Hello Moderators am trying out the API from my server using curl , everything was intight including my authorization code but I was faced with the following error below

cURL Error #:SSL certificate problem, verify that the CA cert is OK. Details: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

1.) What could be the problem. do I have to run the script on HTTPS and not on HTTP

2.) I will like to have your email address so that I can post the code directly to your box

Thanks