Valheim multiplayer not working? Fix it here.

Can't join friends in Valheim

For a self-hosted world, port 2456–2458 must be forwarded, or use the Steam friends 'Join' button.

1. Check and fix your NAT type — Strict NAT is the #1 cause of 'can't join friends'. You need Moderate or Open to host and to receive invites reliably.
   • On Steam: Settings → In-Game → check the 'NAT' indicator, or test via Steam's network settings.
   • On Xbox: Settings → General → Network settings → 'NAT type'.
   • On PlayStation: Settings → Network → View Connection Status → 'NAT Type'.
   • If Strict: enable UPnP and/or port-forward (see those fixes). Tether to a phone hotspot once to confirm — if it works there, the issue is your home router.
2. Use the lobby / join code instead of a friend invite — Steam and platform friend-invites fail far more often than copy-paste codes. Most co-op games have a 'share lobby code' button.
   • Host creates the lobby, then copies the lobby/join code (not the friend invite).
   • Send the code in chat; the joiner pastes it into 'Join with code'.
   • If invites still fail, this bypasses the broken invite pipeline entirely.
3. Port-forward the game's ports — If UPnP alone doesn't help, forward the ports manually so your router routes game traffic to your PC/console. Use the per-game port list on the game's page.
   • Note the ports listed for your game (Steam P2P uses UDP 27015–27030 and UDP 3478 / 4379 / 4380).
   • In your router, create port-forward rules (UDP) pointing to your device's local IP.
   • Set a static LAN IP (DHCP reservation) so the rule keeps working after reboots.
   • Test again — your NAT should now read Moderate or Open.
4. Host starts the world, then friends click 'Join' in their Steam friends list, or connect via IP:2456 (UDP).

Valheim multiplayer not working

1. Power-cycle your router and relaunch the game — A 30-second router reboot clears stale NAT and UPnP leases that silently break peer-to-peer connections. Fully quit the game (don't just minimise) and reopen it.
   • Unplug the router for 30 seconds, then plug it back in and wait for full sync.
   • Completely close the game (check Task Manager / Force Quit — overlays can leave it running).
   • Relaunch the game and try joining again.
2. Enable UPnP on your router — UPnP lets the game open its own port automatically. With it off, you'll often get Strict NAT and can't host or receive invites.
   • Log in to your router admin page (usually 192.168.0.1 or 192.168.1.1).
   • Find 'UPnP' or 'Universal Plug and Play' and turn it ON.
   • Save and reboot the router, then retry the game.
3. Turn off VPN, proxy, and 'kill switch' tools — VPNs and routing tools reroute P2P traffic and trigger Strict NAT or total blocks. Disable them for the session.
   • Fully quit your VPN app (not just disconnect — quit it).
   • Disable any proxy in Windows Settings → Network → Proxy.
   • Temporarily uninstall 'kill switch' / firewall-overlay tools if the issue persists.
   • Retry the join with a direct connection.

Valheim connection failed / world desync

1. Allow the game through firewall & antivirus — Over-aggressive security software flags game executables as threats and drops the connection after join.
   • Windows: Allow the game .exe through Windows Defender Firewall (Private + Public).
   • Add the game and Steam/Epic to your antivirus allow-list.
   • On Mac: System Settings → Privacy & Security → Firewall → allow the game.
2. Verify game files (fixes corrupted installs) — A half-downloaded or corrupted file causes 'connection failed' right after joining. Verifying redownloads the broken bits.
   • Steam: Library → right-click game → Properties → Installed Files → 'Verify integrity of game files'.
   • Epic: Library → three dots → 'Manage' → 'Verify'.
   • Console: a corrupted install usually needs a full reinstall from the store.
3. Use a wired connection to stop lag & drops — Wi-Fi jitter causes 'connection failed' and mid-session drops. A cable removes most of it.
   • Plug in Ethernet instead of Wi-Fi for the host especially.
   • If Wi-Fi only, move close to the router and use 5 GHz.
   • Close bandwidth-heavy apps (streaming, downloads) during play.

Valheim error codes explained

CONNECTION FAILED

Port 2456–2458 not forwarded or NAT Strict. Forward UDP 2456–2458.

DESYNC

Host and client on different versions. Update both.