iOS POST JSON Echo禁止关键字符

Question

NSMutableDictionary *dictionary=[[NSMutableDictionary alloc] init];

[dictionary setObject:self.uniqueKey forKey:@"unique"];


[dictionary setObject:groupArr forKey:@"addressbook"];



if ([NSJSONSerialization isValidJSONObject:dictionary]){

    NSURL *uploadPath=[NSURL URLWithString:@"URL"];

    NSData *data = [NSJSONSerialization dataWithJSONObject:dictionary options:NSJSONWritingPrettyPrinted error:nil];

   }

我想发布这本词典。groupArr由地址簿联系人组成。但是它给了我Echo消息表单服务器Echo Disallowed Key Charatcers我没有得到它正在抛出这个错误