Google Cloud Endpoint API返回500错误

Question

我应用了找到的答案 HTTP code 302 encountered when deploying on Google App Engine Endpoints

302问题消失了，API已在已部署的应用程序中显示，但现在我收到此错误：

{
 "error": {
  "errors": [
   {
    "domain": "global",
    "reason": "internalError",
    "message": "Internal Error"
   }
  ],
  "code": 500,
  "message": "Internal Error"
 }
}

应用程序日志显示此请求的200响应：

2013-03-07 18:57:10.992 /_ah/spi/DeviceSyncEndPoint.listDevices 200 185ms 0kb Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11
216.31.219.19 - - [07/Mar/2013:18:57:10 -0800] "POST /_ah/spi/DeviceSyncEndPoint.listDevices HTTP/1.1" 200 86 - "Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11" "racermanager-hrd.appspot.com" ms=186 cpu_ms=47 cpm_usd=0.000010 instance=00c61b117ceb47410221ae438f2cbe7fc958

500错误来自何处以及如何解决？