The same thing just happened with our application.
Moving it out of the source app worked fine (I assume, since the
Datastore Admin for the source app shows all copy steps completed).
It's been over an hour and the target app is still empty.
This was as a small amount of data. Does it take a long time to move,
or could there be a problem that does not show up in the logs?
Note that I created my own appengine_config.py file in the root
directory of the target app with just one line:
remoteapi_CUSTOM_ENVIRONMENT_AUTHENTICATION =
('HTTP_X_APPENGINE_INBOUND_APPID', ['my source appid here'])
Thanks!