Origin 'null' has been blocked by CORS policy

ERPNext
1

when I send a request to erpnext api using axios or jquery ajax it gives me this error in console

from origin 'null' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

and this my jquery code


var jqxhr = $.ajax({ 
    type:'get',
    dataType:'json',
    contentType:'jsonp',
    url:"<my url endpoint>",
    headers:{
        
            'Access-Control-Allow-Origin' : '*',
            'Access-Control-Allow-Methods' : 'GET,PUT,POST,DELETE,PATCH,OPTIONS',
    } })
  .done(function() {
    alert( "success" );
  })
  .fail(function() {
    alert( "error" );
  })
  .always(function() {
    alert( "complete" );
  });

i just created an index.html and add this script
but when I use python request it works