Objective-C的JSON返回错误"非法启动令牌[r] "

I am attempting to connect to a web page and return a JSON string. This string simply needs to be parsed in JSON and returned into an NSArray that I have waiting for it. The problem is that JSON doesn't always return the results. Sometimes, it works well. Sometimes, it returns (null), citing the error below.I am attempting to connect to a web page and re