I got the MongoId not found error on the the application I recently moved to remote server.
The app is working fine locally and the problem appears to happen on the remote one only.
The problem seems obvious, and I checked the mongo version I have locally vs the version I have on the remote – they are different
I have newer version of mongo installed on the remote server. And the doctrine orm handling my mongo objects was also older.
I updated my doctrie orm on composer as
"doctrine/orm": "2.4.6",
This took care of the problem – at least for now đ