ios AFNetworking预期内容错误

在故障块中得到json字符串：

NSURL *url = [[NSURL alloc] initWithString:@"http://www.vinipost.com/Services/Update/UpdateService.asmx/GetPropSubType?"]; NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url]; [AFJSONRequestOperation addAcceptableContentTypes:[NSSet setWithObject:@"text/html"]];

        AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {

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

输出：

Request Failed with Error: Error Domain=AFNetworkingErrorDomain Code=-1016 "Expected content type {( "text/json", "text/javascript", "application/json", "text/html" )}, got text/plain" UserInfo=0x71521a0 {NSLocalizedRecoverySuggestion=[{"PropTypId":1,"PropCatId":1,"PropTyp":"Flat/ Condo"}.......