This version of Unity is unsupported.
Method group is Obsolete

NetworkManager.dontDestroyOnLoad

Obsolete The high level API classes are deprecated and will be removed in the future. public bool dontDestroyOnLoad;

Description

A flag to control whether the NetworkManager object is destroyed when the Scene changes.

This should be set if your game has a single NetworkManager that exists for the lifetime of the process. If there is a NetworkManager in each Scene, then this should not be set.