angular has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present code example

Example 1: origin 'http://localhost:4200' has been blocked by CORS policy

let headers = new HttpHeaders({
      'Content-Type': 'application/json',
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Headers': 'Content-Type',
      'Access-Control-Allow-Methods': 'GET,POST,OPTIONS,DELETE,PUT',
      'Authorization': 'Bearer szdp79a2kz4wh4frjzuqu4sz6qeth8m3',
    });

Example 2: origin 'http://localhost:4200' has been blocked by CORS policy

'Content-Type': 'application/json',
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Headers': 'Content-Type',
      'Access-Control-Allow-Methods': 'GET,POST,OPTIONS,DELETE,PUT',
      'Authorization': 'Bearer key',