Access-Control-Allow-Origin in ASP.NET webform

I already have added the below header but still gives the same message:

"Access to XMLHttpRequest at 'https://ift.tt/2QoRSxn' from origin 'https://shjrerd.gov.ae' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource."

    <add name="Access-Control-Allow-Origin" value="*" />  
    <add name="Access-Control-Allow-Headers" value="Content-Type" />  
    <add name="Access-Control-Allow-Methods" value="GET,POST,PUT,DELETE,OPTIONS" />  
    <add name="Access-Control-Allow-Credentials" value="true" />