Actual issue

Access to XMLHttpRequest at ‘https://www.domain.com/webservices/login-user-webservice.php’ from origin ‘http://localhost:8100’ has been blocked by CORS policy: Request header field content-type is not allowed by Access-Control-Allow-Headers in preflight response.

you should add following php line in top of page

if (isset($_SERVER['HTTP_ORIGIN']) && $_SERVER['HTTP_ORIGIN'] != '') {

  header('Access-Control-Allow-Origin: ' . $_SERVER['HTTP_ORIGIN']);
      header('Access-Control-Allow-Methods: GET, PUT, POST, DELETE, OPTIONS');
      header('Access-Control-Max-Age: 1000');
      header('Access-Control-Allow-Headers: Content-Type, Authorization, X-Requested-With');
}