iOS Afnetworking: Request failed unauthorized (401)
<p>I'm using afnetworking. And getting error unauthorised 401 on POST request. </p>

<pre><code> AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    manager.requestSerializer = [AFJSONRequestSerializer serializer];
    //[manager.requestSerializer setValue:@"" forHTTPHeaderField:@"auth"];
   //[manager.requestSerializer setValue:@"application/json" forHTTPHeaderField:@"Accept"];
    //[manager.requestSerializer setValue:@"Bearer \(token!)" forHTTPHeaderField:@"Authorization"];
    //sessionManager.requestSerializer.setValue("Bearer \(token!)", forHTTPHeaderField: "Authorization")
    [manager.requestSerializer setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    [manager POST:url parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject){
         NSLog(@"%@", responseObject);
        }
     }
          failure:^(AFHTTPRequestOperation *operation, NSError *error)
     {
         NSLog(@"%@", [error description]);

     }];
</code></pre>