Call plugin error

Hai guys, can any one tell me what is wrong with this

Operation failed: OperationResponse 227: ReturnCode: 32751 (Plugin Mismatch requested='CustomPlugin' got ErrorPlugin with message:'PluginManager initialization failed.')

Iam following tutorial this page
and I am using unity to create room with this code:

RoomOptions RO = new RoomOptions();
RO.MaxPlayers = 4;
ExitGames.Client.Photon.Hashtable CustomRoomProperties = new ExitGames.Client.Photon.Hashtable();
CustomRoomProperties.Add("Password", passwordField.text);
CustomRoomProperties.Add("Play",false);
RO.CustomRoomProperties = CustomRoomProperties;
RO.CustomRoomPropertiesForLobby = new string[] { "Password","Play"};
RO.PublishUserId = true;
RO.Plugins = new string[] { "CustomPlugin" };
PhotonNetwork.CreateRoom(name, RO, TypedLobby.Default);

Please tell me how it's work thanks