Response to preflight request doesn't pass access control check: no 'access-control-allow-origin' header is present on the requested resource

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C#

.NET

Ajax

WebAPI2

i am using ajax for web Api calling from C#.net . When i call the ajax function i geting this error 

<pre>Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:49956' is therefore not allowed access

and my ajax funcion is

$.ajax({
                        url: 'https://xxx.xxx.com/external/xx/token',
                        type: 'POST',
                        data: RequestBody,
                        Accept: 'Application/Json',
                        contentType: 'Application/Json',
                        headers: {
                            'Authorization':'Integration mOB33m0='
                        },
                        beforeSend: function(request) {
                            request.setRequestHeader("Authorization", "Integration bWE3Om0=");
                        },
                        success: function (data) {
                            debugger;
                           
                        },
                        error: function (xhr, textStatus, errorThrown) {
                            debugger;
                          

                        }

                    });

But i run the API through Fiddler the APi works very good. That means API is good there is a problem some were in my code . Where i am wrong .

What I have tried:

search in google but no appropriate answer i found.