After 5 hours searching and trying to do everything to my game. Here is the solution to works it out, if you join or host the game, the multiplayer still show that unavailable however.

When u install the game , steam will install on:
X:\SteamLibrary\steamapps\common\Stronghold Legends

The GameRanger doesn't works very well with steam, so you need to move the hold game to just after the X:\
For example, I cut my 'Stronghold Legends' file(the entire file)
from F:\SteamLibrary\steamapps\common
and move it to F:\
so the game's .exe will be on F:\Stronghold Legends

During moving the files you may have so problem like .dll is using, you need to close your game and steam and also GameRanger.

After you moved your game, GameRanger may say you don't have this game, don't worried, shut down your GameRanger, open your steam and run the game once and close the game, then open the GameRanger, now it works!

Enjoy your game, don't do the searching for 5 hours just like me ;)

If you have a network problem with GameRanger, see here: http://www.gameranger.com/support/network/

Firewell problem: https://www.youtube.com/watch?v=ke9E3AkDR_o

Router Problem: https://www.youtube.com/watch?v=f4OpqTnIlU0

And if you are using a NETGEAR Router DGN2200 without a port forwarding option,
1. Go to Content Filtering - Services

Set up like this











2. Go to Content Filtering - Firewall Rules
LAN Server IP address is your computer IP address which give by the router.
Remember to set up both Outbound Services and Inbound Services as well as apply, and hope it helps :)

And I also find this page on the website of fireflyworlds support, but it seen not working for my games, it's so hard to find this though, hopefully it work for someone of you guys.

and the wesite : http://support.fireflyworlds.com/index.php?/Knowledgebase/Article/View/150/37/stronghold-2-and-stronghold-legends-multiplayer-problems


Stronghold 2 and Stronghold Legends Multiplayer Problems


If you are experiencing issues with Multiplayer games not working. There is a workaround for this problem.

Set your exe file to Windows XP SP3 Compatibility mode and setup a multiplayer game via GameRanger as per normal - http://www.gameranger.com/

You can do this by locating the exe file (default locations listed below) and following the additional instructions.

1.
C:\Program Files (x86)\Steam\steamapps\common\Stronghold 2

C:\Program Files (x86)\Steam\steamapps\common\Stronghold Legends

2. Right click and select Properties.
3. Click on the Compatibility tab.
4. Tick 'Run this program in compatibility mode for:'
5. Select 'Windows XP (Service Pack 3)'
6. Click on OK.
7. Run GameRanger and either Host or Join a game.

The Stronghold Legends Bonus Maps

New Maps:

Devil's Backbone V1 & V2
Swamp
The Hour Glass
The Large FireFly
The small FireFly
The three lords
Too close for comfort

New User Maps:

Alliance Against Evil
Lord of the Mountain Hall
Siegfried, kidnapped!

The New Legends Trail:

Arthur's Challenge


.EXE dowmload:

https://www.dropbox.com/s/wsv5eq0n2rajodv/Stronghold_Legends_Bonus_Maps.exe?dl=0


Problem with showing 'Please install Stronghold Legends before installing Stronghold Legends Bonus Maps.'

You need to creat a .txt and put the text below, Must be the same (including the empty space):

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\strongholdlegends.exe]
"Path"="C:\\Program Files\\2K Games\\Stronghold Legends"
@="C:\\Program Files\\2K Games\\Stronghold Legends\\strongholdlegends.exe"

Remember to change the file path to your own file path, for example, my game is on 'F:\Stronghold Legends', so I need to change it to:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\strongholdlegends.exe]
"Path"="F:\\Stronghold Legends"
@="F:\\Stronghold Legends\\strongholdlegends.exe"

Save it and rename the .txt to .reg, run it, now you can install the Bonus Maps ! ♪(^∇^*)


Note that the file works on WinXP(Service Pack 3) and the above system, not works on Win2000 or older system.