title: "Http failure response for (unknown url): 0 Unknown Error" Angular
body: <p>I try use service httpClient post but I have this error:</p>
  
  <p><a href="https://i.stack.imgur.com/q49od.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/q49od.png" alt="enter image description here"></a></p>
  
  <p>code service:</p>
  
  <pre><code>constructor(private http:HttpClient) { }
  
                Login(data)
                {
  
                  let headers: any = new HttpHeaders();
                  headers.append('Content-Type', 'application/json');
  
                  return this.http.post('link api',data,{headers: headers})
                  .subscribe(res =&gt; console.log(res),err =&gt; { console.log(err);});
  
                }
  </code></pre>
  
  <p>and I try add responseType: 'text' but also error ... I use angular 4</p>