Valheim Server

Why Valheim Says Connection Timed Out — and How to Fix It

“Connection timed out” is not a Valheim-specific error so much as a network one: your client sent packets to an address and port and nothing answered in time. That narrows the causes enormously. Either the server isn’t listening where you’re knocking, something between you and it is dropping UDP, or the server rejected you before completing the handshake — which on a modded server usually means a version mismatch.

Understand what a timeout rules out

A timeout is silence, not refusal. A wrong password produces a password error. A full server produces a rejection. A timeout means your packets went into a void. So stop suspecting the password, the world file, or the player limit — none of those are silent.

Check whether it’s you or everyone. If one person times out and three others are happily playing, the server is fine and the problem is on that one client or their route to you. If nobody can get in, work on the server. This single question saves an hour.

Layer 1: is the server actually running?

Confirm the process exists and finished loading, not just that you started it:

ps aux | grep -i valheim

On Windows, look for the server executable in Task Manager. In Docker:

docker compose ps
docker compose logs --tail=50 valheim

A server that’s still generating a fresh world isn’t listening yet. First boot on a new world can take a while, and every join attempt during that window times out. Wait for the log to report the world loaded and the game server connected.

Also check the machine hasn’t quietly killed it. A server that starts, runs for a minute, and disappears is a crash, not a network problem — see What to Do When Your Valheim Server Keeps Crashing.

Layer 2: the right address and port

You need the public address, not the LAN one. 192.168.x.x and 10.x.x.x addresses only work from inside the same network. Friends need whatever the outside world sees.

Include the game port. Join by IP wants address:port — the game port you configured, 2456 unless you changed it. Pointing a client at the query port instead of the game port times out exactly like a firewall would.

Confirm the port is genuinely open from outside. Test with a friend on another network, not from the same house. Local joins bypass the whole forwarding path and prove nothing.

Layer 3: UDP, firewalls, and NAT

Valheim uses UDP. Three things routinely eat it:

  • A TCP-only forwarding rule. The single most common cause. Recheck the protocol field in the router.
  • The host firewall. Forwarding delivers traffic to the machine; the OS firewall still has to allow it. On Linux, sudo ufw allow 2456:2458/udp; on Windows, an inbound UDP rule for the same range.
  • Carrier-grade NAT or double NAT. If your ISP doesn’t give you a public address, no rule can help. The tell is a private-looking WAN address on the router’s status page.

How to Port Forward a Valheim Server covers each of these with the exact fields to check.

On a VPS there’s no router, but there are usually two firewalls: the provider’s cloud-level rules and the OS firewall inside the instance. Both need the UDP range. Opening one and forgetting the other produces a textbook timeout.

Layer 4: version mismatch

A client on a different build than the server can fail to complete the handshake. The sequence that catches everyone: the game updates, Steam patches your client automatically, and the server is still on last week’s build because nothing told it to update. Re-run the SteamCMD update command and restart:

steamcmd +force_install_dir /path/to/server +login anonymous +app_update 896660 validate +quit

If you run the Docker image with automatic updates enabled, confirm from the logs that the update actually happened rather than assuming it did.

Layer 5: mods

Modded servers add a whole extra class of timeout. If BepInEx and a plugin set are involved:

  • A required mod missing on the client can drop the connection before it establishes, which surfaces as a timeout rather than a helpful message.
  • Mismatched mod versions do the same thing. “Same mod” is not enough; it has to be the same version.
  • A plugin that throws on connect can wedge the handshake server-side. Read BepInEx/LogOutput.log on the server around the timestamp of the failed join — that’s where the real error lives.

The fix is process, not cleverness: one shared mod profile, exported and imported by everyone, as described in Installing Valheim Mods on Your Server with BepInEx. To confirm mods are the cause, launch the server without BepInEx once and try to join vanilla. If that works, the answer is in your plugin list.

Layer 6: the client side

When it’s only one person:

  • Have them restart the game fully. A stale session in the client is real and common.
  • Check they’re not on a VPN. Commercial VPNs frequently break UDP game traffic, or exit in a country with a route that drops it.
  • Verify their game files through Steam if they’ve been fiddling with mods.
  • Try a favourite instead of typing the IP. Typos in an address look exactly like a firewall problem.

A fast triage order

  1. Is anyone connected? (Yes → client-side problem.)
  2. Does the server process exist and has the world finished loading?
  3. Does a join from outside the network work on the game port?
  4. Is the forwarding rule UDP, with matching internal/external ports, and does the host firewall allow it?
  5. Are server and client on the same game build?
  6. Are mod lists identical, and what does the server’s BepInEx log say?

Work down that list rather than changing several things at once. Timeouts are boring failures with boring causes, and the ordering is what keeps you from chasing the wrong one.

troubleshootingnetworkingmods