Blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource

[admin]

I'm using WordPress and from the code i have added a json get request.
This json result is hosted on other server in asp.net platform below is my code :

var getJSON = function(url, callback) {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', url, true);
    xhr.withCredentials = true;
    xhr.responseType = 'json';
    xhr.onload = function() {
        var status = xhr.status;    
        if (status == 200) {
            callback(null, xhr.response);
        } else {
            callback(status);
        }
    };

    xhr.send();

};

getJSON('....api/data/Getallunits',  function(err, data) {
    mydata = data;
});

I'm getting this error:

"Access to XMLHttpRequest at '...../api/data/Getallunits' from origin 'mywordpress' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource."

Is there anything can be done by adding in wordpress, any phpcode or any plugin
i tried with WP-CORS plugin but didn't worked, please advice if any code should be added on the json get request or any other edits.