gae error : Error: Server Error, how to debug it

when i upload my project to google-app-engine , it show this :

Error: Server Error
The server encountered an error and could not complete your request.

If the problem persis开发者_StackOverflowts, please report your problem and mention this error message and the query that caused it.

why ?

how can i debug this error ?

thanks

Look at the logs in the online administrative console of your App Engine account. That's where the info about the "why" hides;-).

Incidentally, it's very unlikely (although not impossible) that you'd immediately see such an error on the actual online App Engine without hints in your local development toolkit environment -- have you thoroughly exercised your app in the SDK before uploading it?