title: Can't get HTML code AFNetworking 2.0
body: <p>I tried to make GET HTTP response. I need to get the html code for the subsequent parsing, but responseObject is nil.</p>
  
  <pre><code>AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
  manager.responseSerializer.acceptableContentTypes = [NSSet setWithObject:@"text/html"];
  
  [manager GET:@"http://www.example.com/" parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
      NSError *error;
      HTMLParser *parser = [[HTMLParser alloc] initWithString:responseObject error:&amp;error];       
  } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
      NSLog(@"Error: %@", error);
  }];
  </code></pre>