Uncaught PHP Exception Doctrine\ORM\ORMException: "Unknown Entity namespace alias 'AppBundle'."
The solution is delete the cache files, so it is needed if you are working in production mode. In debug mode this is done automatically. For be sure, do that manually just dropping the prod folder under var if you are in 3.x, in 2.x under app.
The command to clear the cache for 2.x is:
php app/console cache:clear --env=prod