Connection error

Figured I'd make a new thread.

So I'm able to initiate a connection to a room through HLAPI after realizing that ListMatches works slightly differently in Thunder than it does in UNet. The issue I have now is that I get two errors when a client attempts to connect to a room.

Wrong ip address {} or port {63992}
ConnectToNetworkPeer Error: 8

Digging through the source it looks like the error code is being set in TransportAdapter.ConnectToNetworkPeer but that's as far as Rider will provide insight (TransportAdapter is abstract so it just sorta shrugs at that point).

The host logs the following

and also logs
NetworkServerSimple listen 54593
NATServer created: Listening on port 54593


  • I switched the config to just always use Relay and never attempt punchthrough and that resolved it.
  • Yes, this it Thunder trying to do the punchthrough process.

    Have you tried to run your game into another network ?

    Some NAT device (wireless router, modem or similar) do not support "NAT Hairpinning" (, and not allow two host in the same network to directly connect to each other using external gateways.

    We will be looking at the reason Thunder do not fallback to relay connection automatically.