title: AFNetworking 2.0 POST issue, Cocoa error 3840(JSON text did not start with array...)
body: <p>I am attempting to call api.php on my local server(using MAMP).
  The server side api.php is being called but the content of _POST inside the php code contains the following error:</p>
  
  <pre><code>Error Domain = NSCocoaErrorDomain Code = 3840 "The operation couldn’t be completed. (Cocoa error 3840.)" (JSON text did not start with array or object and option to allow fragments not set.) UserInfo = 0x15d7bdd0 {NSDebugDescription = JSON text did not start with array or object and option to allow fragments not set.}
  </code></pre>
  
  <p>My app that is trying to send the JSON POST request to the api.php is an iOS app using AFNetworking 2</p>
  
  <p>This is my request code:</p>
  
  <pre><code>- (void)postUpdateRequest
  {
      if (!dataModel)
          dataModel = [[DataModel alloc] init];
  
      NSDictionary *params = @{@"foo": @"bar2"};
  
      NSLog(@"%@",params);
  
  /*    NSDictionary *params = @{@"cmd":@"update",
                               @"user_id":[dataModel userId],
                               @"token":[dataModel deviceToken]
                               };//@"ip_address":[dataModel getIPAddress]};*/
  
      AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
  //    manager.requestSerializer = [AFJSONRequestSerializer serializer];
  
      [manager POST:ServerApiURL parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject) {
          NSLog(@"JSON: %@", responseObject);
      } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
          NSLog(@"Error: %@", error);
      }];
  }
  </code></pre>
  
  <p>I looked all over the internet but can't find an answer for my specific problem.
  No matter what I do I get the same error back.</p>
  
  <p>Why is my JSON not properly formatted? I also can't seem to find a way to sniff what JSON I am actually sending.</p>
  
  <p>Thank you.</p>