This version of Unity is unsupported.
Removed in version 2018.4.36

Network.incomingPassword

Obsolete The legacy networking system has been removed in Unity 2018.2. Use Unity Multiplayer and NetworkIdentity instead. public static string incomingPassword;

Description

Set the password for the server (for incoming connections).

This must be matched in the Network.Connect routine on the clients. Pass "" to specify no password (this is default).