"Over QuotaThis Google App Engine application is temporarily over its serving quota. Please try again later."
It seems that i had a small mistake which caused runtime exceptions in some of the requests, This small mistake cause my web site to shutdown for several hours!!!!
I really don't understand Google making this error apeear, I understand that they want to secure their servers but why to shutdown an application for several hours, once the error was fixed the server should be activate again.
Now that the server is done, and many users see the error they won't use the application again!
For this reason I really don't recomment you use Google App Engine.