ICARUS Dedicated Server Troubleshooting Guide

ICARUS Dedicated Server Troubleshooting Guide

This guide covers the most common issues encountered when running an ICARUS dedicated server and how to resolve them.

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Problem: Server Shows in Browser But Players Can't Connect

Symptom: The server appears in the Steam server browser, but players receive a timeout error when trying to join.

Cause: UDP port 17777 is blocked by the firewall.

Fix: Open UDP port 17777 on your server firewall:

# UFW
ufw allow 17777/udp

# iptables
iptables -A INPUT -p udp --dport 17777 -j ACCEPT

Also verify the port is open at the router level if hosting on a home connection.

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Problem: Server Does Not Appear in Steam Browser

Symptom: The server is running but does not show up in the Steam server browser.

Cause: UDP port 27015 (Steam query port) is blocked.

Fix: Open UDP port 27015:

# UFW
ufw allow 27015/udp

# iptables
iptables -A INPUT -p udp --dport 27015 -j ACCEPT

See ICARUS Dedicated Server Port Forwarding for full port configuration details.

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Problem: Server Auto-Shuts Down When Players Leave

Symptom: The server stops running shortly after all players disconnect.

Cause: ShutdownIfNotJoinedFor is set to a non-zero value (default is 300 seconds).

Fix: Open Icarus\Saved\Config\WindowsServer\ServerSettings.ini and set:

ShutdownIfNotJoinedFor=0

Restart the server. See Configuring ICARUS Server Shutdown Behavior for more detail.

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Problem: Prospect Won't Load / Server Starts But No Prospect Is Active

Symptom: The server starts but players cannot join a prospect, or the prospect specified in ServerSettings.ini fails to load.

Cause: The prospect name in ServerSettings.ini does not exactly match the .json file name in Icarus\Saved\PlayerData\DedicatedServer\Prospects\.

Fix: Check the exact file name in the Prospects\ directory and update ServerSettings.ini to match, including capitalization:

# If the file is "MyProspect.json", use:
ResumeProspect=MyProspect

# NOT:
ResumeProspect=myprospect
ResumeProspect=MYPROSPECT

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Problem: Mods Are Not Loading

Symptom: Mods placed on the server are not active in-game.

Cause: The mods folder is named incorrectly (most commonly Mods with a capital M instead of mods).

Fix: Ensure the folder is named with an all-lowercase mods:

Icarus\Content\Paks\mods\    ← Correct
Icarus\Content\Paks\Mods\    ← Wrong — rename to lowercase

Also confirm:

• Files have a .pak extension
• The server was restarted after adding mods
• Players also have the mod installed client-side

See Installing Mods on Your ICARUS Dedicated Server for the full guide.

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Problem: "Connection Failed" or "Session Not Found" Error

Symptom: Players can see the server but receive a "Connection Failed" or "Session Not Found" error.

Possible Causes and Fixes:

1. Version mismatch: The server and client are on different ICARUS versions. Update the server: steamcmd +login anonymous +app_update 2089300 validate +quit
2. Password required: The server has a JoinPassword set. Share the password with players.
3. Server full: Check MaxPlayers in ServerSettings.ini — the hard cap is 8.
4. No prospect loaded: Confirm a prospect is active on the server (check ResumeProspect or LoadProspect in config).

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Problem: High Ping / Lag for Players

Symptom: Players report high latency or rubber-banding.

Fix: Check the following:

• Confirm UDP 17777 is not being throttled or rate-limited
• Verify the server has at least 4 GB RAM available
• Check CPU usage — high CPU under load may indicate a need to upgrade your plan
• Ensure the server region is close to your player base

See ICARUS Dedicated Server Performance Tuning for a full optimization guide.

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Checking Server Logs

For any issue not covered above, the server log is the best diagnostic tool. Logs are stored at:

Icarus\Saved\Logs\

When running with the -log flag, output also appears in the server console. Look for Error or Warning entries near the time of the problem.

Related

• ICARUS Dedicated Server Port Forwarding
• Configuring ICARUS Server Shutdown Behavior
• Host an ICARUS server with DustBowl.Games