Facing cross-domain issue, getting error_code 1000 in jsonp response while http status is 200

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JSONP

CrossBrowser

Hi,
There is REST API, from which I am trying to fetch response.
Issue is if I use JSONP to overcome cross-domain issue then I get error_code:1000 in console.
This is the response I get in console:

Object {header: Object, body: Object}
body:Object
error_code:1000
__proto__:Object
header:Object
__proto__:Object

This is my AJAX call looks like

$.ajax({
        type: 'GET',
        url: 'for security reason I cannot display API URL',
        dataType: 'jsonp',
        data: {
            authtoken: AppFramework.constants.AUTHTOKEN
        },
        success: function(result) {
            console.log(result) ;

        }
    });
};

Is this a whitelisting issue? I am unable to identify. Please suggest.

What I have tried:

When I use data type as JSON, it gives cross domain error.
I get below error.

XMLHttpRequest cannot load https://www.site24x7.com/api/reports/availability_summary?period=3&authtoken=2f8671565a3cbb9e44b858160355ad7c. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://127.0.0.1:59185' is therefore not allowed access.