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Icarus Network Error 65 Fix

Icarus Guide • Updated Mar 29, 2026

Icarus Network Error 65 Fix

Network Error 65 remains one of the most repeated Icarus dedicated-server complaints. Players can see the server, try to join, and then fail during the network handshake. Community troubleshooting kept landing on the same practical answer: fix the Unreal network driver settings first, then verify the normal firewall and version checks.

Known-Good Engine.ini Baseline

Apply the same network driver block to the server and, when needed, to affected clients.

[/Script/OnlineSubsystemUtils.IpNetDriver]
MaxClientRate=100000000
MaxInternetClientRate=100000000
InitialConnectTimeout=120.0
ConnectionTimeout=120.0
NetServerMaxTickRate=30
LanServerMaxTickRate=35
RelevantTimeout=5.0
KeepAliveTime=0.2
MaxPortCountToTry=512
ServerDesiredSocketReceiveBufferBytes=131072
ServerDesiredSocketSendBufferBytes=131072
ServerDesiredSocketReceiveBufferBytes=131072
ServerDesiredSocketSendBufferBytes=131072
MaxSecondsInReceive=0.5
NbPacketsBetweenReceiveTimeTest=2

Where to Place It

System Typical Path
Dedicated server Icarus/Saved/Config/WindowsServer/Engine.ini
Player client %localappdata%/Icarus/Saved/Config/WindowsNoEditor/Engine.ini

Fix Checklist

  1. Add the network block to the dedicated server and restart it fully.
  2. Retest with the host plus one external player, not just the local machine.
  3. Confirm the server and client are on the same game build.
  4. Verify the game port and query port are open and not reused by another service.
  5. If only one player still fails, apply the same Engine.ini block to that client.

Error 65 is not always a port-forwarding problem. If the session is visible but the connection dies during join, the Unreal network tuning fix is often faster than randomly changing firewall rules.

Need a cleaner Icarus baseline with fewer join issues to chase? Launch an Icarus dedicated server on Supercraft and start from a stable hosting setup.

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