Dedicated Server fails all P2P connections on Windows Server 2025 (Peer2Peer_ConnectionFailed Timeou
Hello,
I am experiencing a critical issue where no players can connect to my Space Engineers Dedicated Server. Every connection attempt times out with this message in the server log:
Peer2Peer_SessionRequest Peer2Peer_ConnectionFailed Timeout
This happens 100% of the time and the server is completely unreachable.
But the server is visable and pingable in the server browser...
Below is the log excerpt:
2025-12-03 11:18:21.790: Peer2Peer_SessionRequest [xxx] 2025-12-03 11:18:36.786: Peer2Peer_ConnectionFailed [xxx], Timeout
Full server startup log (relevant parts):
App Version: 01_208_015 Networking service: Steam Server connected to Steam Public IP: 82.xxx.xxx.xxx Server Name: The Survivalists World Name: Alien Planet Game ready... Plugin Init: MultigridProjectorDedicated.MultigridProjectorPlugin Peer2Peer_SessionRequest Peer2Peer_ConnectionFailed Timeout
The server never reaches “GameServer Logged On” in the logs, which normally appears when SteamNetworking initializes correctly.
Environment
- OS: Windows Server 2025 Standard
- CPU: Ryzen 9 9900X
- Steam logged in and running
- Space Engineers Dedicated Server installed via Steam
- No NAT (dedicated host, public IPv4)
- Ports open: 27015 / 27016 / 8766 / 27000–27050
- DDoS filtering disabled for testing
- Windows Firewall on/off tested
- Fresh world created
- Tested with and without mods
- Tested with and without plugins
- Clean reinstall of the Dedicated Server
Troubleshooting already doneI have tested everything I can think of:
- Fully disabled Windows Firewall
- Fully allowed all SE and SteamNetworking ports
- Verified external port accessibility
- Disabled DDoS filtering
- Tried different game ports (27016, 29016, etc)
- Reinstalled the entire Dedicated Server
- Tested fresh empty world
- Tested vanilla (no mods)
- Tested plugins disabled
- Restarted Steam and OS multiple times
- IPv6 on and off tested
- Verified that Steam reports “Server connected to Steam”
None of these changed the behavior.
All clients still get stuck at “Connecting…” and eventually time out.
I also want to mention that I host other game servers on the same machine without any issues, Arma, DayZ, Valheim, Farming Sim 25 etc. etc.
Important finding On Windows Server 2025 the server never outputs:
GameServer Logged On
and SteamNetworking appears to initialize only partially.
Because of this, every incoming connection ends in:
<div><div><div></div></div><div><code>Peer2Peer_ConnectionFailed Timeout </code></div></div>
I have the same bug
Hello!
Thank you for contacting us. Since this is a bug report, I'm moving your ticket to our support page, where our QA team will take care of you.
Kind Regards
Keen Software House
Hello!
Thank you for contacting us. Since this is a bug report, I'm moving your ticket to our support page, where our QA team will take care of you.
Kind Regards
Keen Software House
Hello Engineer,
Thank you for the detailed report and for sharing your findings.
Could you please provide the game and server log files?
Normally, the logs are stored in the following location.
This information should help you locate the log files on your Windows Server system. Having the logs will be a good starting point for us to investigate the issue further.
Thank you for your understanding.
Kind Regards,
Keen Software House: QA Department
Hello Engineer,
Thank you for the detailed report and for sharing your findings.
Could you please provide the game and server log files?
Normally, the logs are stored in the following location.
This information should help you locate the log files on your Windows Server system. Having the logs will be a good starting point for us to investigate the issue further.
Thank you for your understanding.
Kind Regards,
Keen Software House: QA Department
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