title: Domain=NSCocoaErrorDomain Code=3840 error in afnetworking 2.0
body: <p>i am unable to find solution of NSCocoaErrorDomain Code=3840  error in afnetworking 2.0 </p>
  
  <p>this is code i used </p>
  
  <pre><code>AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
  manager.responseSerializer.acceptableContentTypes = [manager.responseSerializer.acceptableContentTypes setByAddingObject:@"text/html"];
  
      [manager POST:url parameters:inputs success:^(AFHTTPRequestOperation *operation, id responseObject)
      {
  
           NSLog(@"JSON: %@", responseObject);
  
      }
            failure:^(AFHTTPRequestOperation *operation, NSError *error) {
          NSLog(@"Error: %@", error);
      }];
  </code></pre>
  
  <p>this is the error getting</p>
  
  <pre><code>Error: Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.}
  </code></pre>