We are currently experiencing production issues with Google App Engine. Master/Slave applications may be experiencing performance degradation up to total unavailability. No disruption is expected for High Replication apps. The App Engine admin console is currently unavailable.
We are actively working on resolving the issue, and I will post updates as they are available. I sincerely apologise for the inconvenience this causes, and we're attempting to resolve the issue as soon as possible.
Nick Johnson, Developer Programs Engineer, App Engine