it references interface "Doctrine\Persistence\ObjectManager" but no such service exists. You should maybe alias this interface to the existing "doctrine.orm.default_entity_manager" service. code example

Example: it references interface "Doctrine\Persistence\ObjectManager" but no such service exists. You should maybe alias this interface to the existing "doctrine.orm.default_entity_manager" service.

You should avoid using directly the service. Always use the contract instead. It is available for every services

So instead of using ObjectManager directly, use EntityManagerInterface