Google app engine sample app throwing 503

Question

I have setup Google app engine's sample android from this tutorial

when I type something into the EditText and press Send Button, nothing happens for a while and throws the following error

06-10 18:47:49.109: I/CloudBackend(28741): error: 
06-10 18:47:49.109: I/CloudBackend(28741): com.google.api.client.googleapis.json.GoogleJsonResponseException: 503 Service Unavailable
06-10 18:47:49.109: I/CloudBackend(28741): {
06-10 18:47:49.109: I/CloudBackend(28741):   "code": 503,
06-10 18:47:49.109: I/CloudBackend(28741):   "errors": [
06-10 18:47:49.109: I/CloudBackend(28741):     {
06-10 18:47:49.109: I/CloudBackend(28741):       "domain": "global",
06-10 18:47:49.109: I/CloudBackend(28741):       "message": "",
06-10 18:47:49.109: I/CloudBackend(28741):       "reason": "backendError"
06-10 18:47:49.109: I/CloudBackend(28741):     }
06-10 18:47:49.109: I/CloudBackend(28741):   ],
06-10 18:47:49.109: I/CloudBackend(28741):   "message": ""
06-10 18:47:49.109: I/CloudBackend(28741): }
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:111)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:38)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.api.client.googleapis.services.AbstractGoogleClientRequest$1.interceptResponse(AbstractGoogleClientRequest.java:314)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1060)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:412)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:345)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:463)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.cloud.backend.android.CloudBackend.insert(CloudBackend.java:111)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.cloud.backend.android.CloudBackendAsync.access$0(CloudBackendAsync.java:1)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.cloud.backend.android.CloudBackendAsync$1.callBackend(CloudBackendAsync.java:87)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.cloud.backend.android.CloudBackendAsync$1.callBackend(CloudBackendAsync.java:1)
06-10 18:47:49.109: I/CloudBackend(28741):  at com.google.cloud.backend.android.CloudBackendAsync$BackendCaller.run(CloudBackendAsync.java:428)

It is very annoying that the message is "" ! P.S: I am new to Google app engine.

Answer 1

It could probably a data conversion error. The server is expecting values in one format and client is sending in some other format (parsing layer issue in google cloud endpoint). I would highly suggest you to make use of google's api explorer tool to verify first that your server side interface is working without any problem. Then you should move on find out any problems with client side.