Ios 解析导致rest api不工作的原因

我正在调用parserestapi。我已经添加了以下代码，但现在正在工作

let request = NSMutableURLRequest()
    request.HTTPMethod = "GET"
    request.addValue("XX", forHTTPHeaderField: "X-Parse-Application-Id")
    request.addValue("XXX", forHTTPHeaderField: "X-Parse-REST-API-Key")
    request.addValue("application/json", forHTTPHeaderField: "Content-Type")
    request.addValue("application/json", forHTTPHeaderField: "Accept")
   let oneHourAgo = NSDate(timeIntervalSinceNow: (-3600))
   let  urlString = NSString(format: "https://api.parse.com/1/classes/Sample?&limit=%d&skip=%d&where={\"createdAt\":{\"$gt\":\"%@\"}}",1000,skipValue,self.getISOStringFromDate(oneHourAgo))

let task = NSURLSession.sharedSession().dataTaskWithRequest(request, completionHandler: { (data, response, err) -> Void in
        do {
            print(err);
        } catch {
            print("json error: \(error)")
        }

    })

输出错误：

UserInfo={NSUnderlyingError=0x7af94cb0{Error Domain=KCferrordomaincfn网络代码=-1002“（null）”}，NSLocalizedDescription=unsupported URL}）