Ios – AFNetworking and POST Request

I'm getting this response in error.userInfo while making a POST request from AFNetworking.
Can anyone tell either I'm missing anything obvious or something need to fix at my server end?

Request Failed with Error: Error Domain=AFNetworkingErrorDomain
Code=-1016 "Expected content type {(
"text/json",
"application/json",
"text/javascript" )}, got text/html" UserInfo=0x6d7a730 {NSLocalizedRecoverySuggestion=index test,
AFNetworkingOperationFailingURLResponseErrorKey=, NSErrorFailingURLKey=http://54.245.14.201/,
NSLocalizedDescription=Expected content type {(
"text/json",
"application/json",
"text/javascript" )}, got text/html, AFNetworkingOperationFailingURLRequestErrorKey=http://54.245.14.201/>}, {
AFNetworkingOperationFailingURLRequestErrorKey = "http://54.245.14.201/>";
AFNetworkingOperationFailingURLResponseErrorKey = "";
NSErrorFailingURLKey = "http://54.245.14.201/";
NSLocalizedDescription = "Expected content type {(\n \"text/json\",\n \"application/json\",\n
\"text/javascript\"\n)}, got text/html";
NSLocalizedRecoverySuggestion = "index test"; }

And I'm using this code;

AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:url];
[httpClient registerHTTPOperationClass:[AFJSONRequestOperation class]];
[httpClient setDefaultHeader:@"Accept" value:@"application/json"];
NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:
                        @"Ans", @"name",
                        @"29", @"age",
                        nil];

NSMutableURLRequest *request = [httpClient requestWithMethod:@"POST" path:@"/" parameters:params];

AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
    success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
        NSLog(@"Success");
        NSLog(@"%@",JSON);

    } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {
        NSLog(@"Request Failed with Error: %@, %@", error, error.userInfo);
        NSLog(@"Failure");
}];

[operation start];
[operation waitUntilFinished];