iOS - when I am posting more than 130 fields in objective c there taking 125 fields only other 5 fields taking as a null value? why

/*** Create JSON ***/
NSMutableDictionary *nameElements = [NSMutableDictionary dictionary];
[nameElements setObject:@"1" forKey:@"MemberID"];
[nameElements setObject:@"Weerachai" forKey:@"Name"];
[nameElements setObject:@"0819876107" forKey:@"Tel"];
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:nameElements
                                                   options:NSJSONWritingPrettyPrinted
                                                     error:nil];