Thank you for the response, I have changed those two lines.
The Entities Mapping error is now gone and shows no errors, thank you for that.
But I still can't get access to the backend site, unless I set _PS_MODE_DEV_ to true
In the debug log center I can only seem to find this error under Deprecations:
| Time | Channel | Message |
|---|---|---|
| 23:43:46 | - | Enabling the "sensio_framework_extra.router.annotations" configuration is deprecated since version 5.2. Set it to false and use the "Symfony\Component\Routing\Annotation\Route" annotation from Symfony itself. |