Valheim 'Failed to connect' and other join errors fixed

Valheim's connection errors split cleanly into two kinds. "Failed to connect" means the player's packets never got a useful answer from the server - a wrong address or port, a closed UDP port, or a server that is not running or not ready yet. Every other message - "Incompatible version", "Server is full", "Incorrect password", a ban - means the connection worked and the server turned the player away for a stated reason. So the first question is not "what is wrong with the server" but "did the player reach it at all", and the server log answers that in seconds. This post goes through each message, what causes it, and the order to check things in, with the deeper fixes left to the posts that cover them.

Read the server log first#

Every rejection that reaches the server is logged. Every failure that does not reach it leaves nothing. That makes the log the fastest diagnostic you have.

Have the player try once while you watch the console. Then:

The exact wording of these lines changes between builds, and a modded server adds lines of its own from BepInEx and its plugins, but each attempt that arrives names the player's ID. That ID also tells you which player it was, which matters when three people are trying at once.

On your own machine the log is the server's standard output or the file set with -logFile. On a panel host it is the console. On the player's side, the game writes Player.log in the save folder - on Windows, %USERPROFILE%\AppData\LocalLow\IronGate\Valheim\Player.log - which sometimes carries more detail than the popup. Valheim save locations lists where the rest of the files are.

"Failed to connect"#

The client sent connection attempts and gave up waiting. Nothing about versions, passwords or bans is involved, because the server never got far enough to check them.

Causes, roughly from most to least common:

1. Wrong port. Joining by IP uses the game port - 2456 by default, or whatever -port says. People type the query port 2457 because a host's panel listed it, or leave the port off on a server that does not use the default.
2. UDP not open. The server runs, the address is right, but a firewall or router lets only TCP through, or opens only the game port without the one above it. Valheim is UDP throughout. Valheim ports 2456 and 2457 explained goes through opening and forwarding them properly.
3. The server is still starting. A big world takes time to load, and the server also has to register with Steam before Steam players can connect. Attempts made in the first minute after a start can fail. Wait for the log to show the world loaded and the server connected to Steam, then try again.
4. The server is not running. It crashed, or it is stuck in a restart loop. Valheim server crashes on start covers the start-up failures; why your game server keeps restarting covers the loop.
5. Wrong address. An old IP from before the host or the home connection changed, a typo, or a domain whose record still points somewhere else.
6. The player is on the same network as a home server, using its public address, and the router has no NAT loopback. They should use the LAN address instead.

The fastest split between these is a second player. If anyone outside your network can join, the server and its ports are fine and the problem is on the failing player's side or in the address they typed. If nobody can, it is the server or the path to it.

On the player's side, two things occasionally cause a genuine "Failed to connect" to a working server: a restrictive network (a university or workplace network that blocks unusual UDP) and a VPN that does not pass UDP. Trying from a phone hotspot rules both out in a minute.

Failed to connect through the server list

A server picked from the community list can also fail when the list entry is stale - the server restarted on a different port, or the entry is from a previous session. Join by IP to confirm. If join by IP works and the list does not, see Valheim server not showing in the list for why the list lags behind.

"Incompatible version"#

The client and the server are on different builds. The game updates through Steam on its own; the dedicated server updates only when someone runs an update on it. On the day of a patch, this message is expected.

The checks:

• Compare the version on the player's main menu with the Valheim version line near the top of the server log.
• If the server is older, update it - a clean stop, +app_update 896660 through SteamCMD, start again.
• If the player is older, they restart Steam and let the game update. A player on the public test branch has to opt out of it in Steam to join a normal server.
• On a crossplay server, an Xbox or Microsoft Store player may simply be a day behind Steam players after a patch; theirs arrives later.

On a modded server, do not update the server just because the game updated. Wait for your mods. The whole routine, including the public test branch and how to time updates for a group, is in updating a Valheim server and fixing version mismatches.

A mod version mismatch is a different error. With Jotunn-based mods, or mods that use ServerSync, a player whose mod set does not match the server's gets a popup listing the mods that differ, often after the game itself has accepted them. The game's own "Incompatible version" is only about the game build. Valheim mod version mismatch kicks covers the mod one.

"Server is full"#

The server already has its maximum of ten players. That limit is built into the game; it is not a setting and no plan or host changes it. Only mods raise it, with consequences covered in the Valheim player limit and larger groups.

When the server says it is full and you count fewer than ten people, the usual cause is a ghost session. A player whose game crashed or whose connection dropped is still counted until the server notices they are gone. A few minutes later the slot frees up on its own.

What to do:

• Wait a minute or two and try again. Most ghost sessions time out quickly.
• Check the player list. An admin can see who the server thinks is online; a name of someone who has clearly left is a ghost.
• Restart only as a last resort, and cleanly, so the world saves. A restart clears every ghost at the cost of a short interruption for everyone else.

A related message appears when a player who has just crashed rejoins before their old session has gone: the server sees the same ID already connected and refuses the second one. Same fix - wait for the old session to time out.

"Incorrect password"#

The server has a password and the player sent the wrong one. The password prompt appears when they join; the error follows if what they typed does not match.

Things that catch people:

• Case and spaces. The password is matched exactly. Herring42 is not herring42, and a trailing space pasted from a chat message counts.
• The password changed. If the server's -password changed, every player needs the new one. Players who saved the server in their recent list are not told.
• Two servers, two passwords. On a machine running more than one server, the player may be joining the right address with the wrong port, and so the wrong server's password.
• Keyboard layout. A player on a different layout typing a password with y, z or symbols may enter different characters than they think.

A password must be at least five characters and must not appear in the server name or the world name, or the server refuses to start at all - that is a start-up failure, not this error, but it is why people's chosen passwords sometimes get changed by whoever fixes the server.

You cannot see the password from inside the game. On your own machine it is in the start script or service file; on a panel host it is one of the startup variables. On RE:NODE a join password is generated for a new Valheim server and shown with the startup variables on the Startup tab, where it can also be changed - restart the server afterwards for the change to take effect.

Banned, or not on the allow list#

A player who is in bannedlist.txt is turned away at connection. So is a player missing from permittedlist.txt when that file contains any IDs at all, because a non-empty allow list makes the server private. The game does not tell the player which list stopped them - in current builds the refusal looks the same either way, so a player who "has been banned" on a server nobody banned them from has usually been left off an allow list.

Check, in the server's save folder:

• `bannedlist.txt` for the player's ID.
• `permittedlist.txt` - if it has any IDs, is this player's ID among them, in the right form? On a crossplay server, IDs are platform-prefixed (Steam_76561198012345678), and a bare SteamID64 in the file does not match.
• That you are editing the right file. The server reads the lists in its own save folder, not the install folder and not your PC.

The file format, the ID forms and how to find a player's exact ID are in Valheim adminlist, bannedlist and permittedlist.

"Disconnected" during play#

The player was in the world and was dropped. Unlike the errors above, this happens after a successful join, so the cause is something that ended the session.

Everyone at once. Look at the server's uptime and the log. A restart nobody announced, a crash, or a memory limit reached will all do it. A server that runs out of memory is stopped; on RE:NODE it is restarted clean rather than left to swap, but the players still drop and anything since the last save is lost. Valheim server performance and lag covers sizing.

Everyone at an interval. On a very large world, the save can freeze the server long enough for clients to give up. If drops line up with -saveinterval, the save is the cause; a faster disk, a trimmed world and a shorter interval (smaller saves, more often) all help.

One player. Their wifi, their router, a VPN, or their PC stalling. Ask them to test on a wired connection. Packet loss is the usual root cause - latency, jitter and packet loss shows how to tell.

Right after joining. On a modded server, a Jotunn or ServerSync version check that fails often lets the player in and then disconnects them, sometimes with a message, sometimes with only "Disconnected". Compare mod lists. On any server, an admin kick or ban also looks like this from the player's side.

Crossplay and join code problems#

With -crossplay, joining by six-digit code has failures of its own:

• The code is old. It changes every time the server restarts. A code from yesterday's chat message leads nowhere. Read the current one from the console.
• The Xbox account blocks it. Xbox privacy settings that forbid joining multiplayer games or communicating with players outside Xbox stop crossplay joins with an error about privileges, not about the server.
• The server is not actually in crossplay mode. Without -crossplay, there is no code and Xbox players cannot join at all.
• The relay is slow to register. Right after a start, the code may not resolve for a short while. Wait and retry before changing anything.

Valheim crossplay and Xbox players covers the account settings and how platform IDs affect the list files.

A checking order that works#

When someone cannot join, work through this in order and stop at the first thing that is wrong:

1. Is the server running, and has it finished loading? Read the last lines of the console.
2. Can anyone else join? If yes, focus on the one player.
3. Did the attempt appear in the log? If no, check address, port number, UDP and firewall.
4. If it appeared, what reason did the server give? Version, password, list file or full.
5. If they got in and were dropped, was it everyone or one player, and at what moment?

FAQ#

Why does Valheim say Failed to connect when the server is online?

Because the player's packets are not reaching it. Check they are using the game port, not the query port, that UDP is open, and that the server had finished loading. If nothing appears in the server log, it is the path, not the game.

Why can I join by IP but not from the server list?

The game port works and the list is stale or slow. The community list takes several minutes to pick up a server and can hold old entries. Joining by IP is the more reliable method anyway.

How do I fix Incompatible version on a modded server?

Wait for every mod you use to support the new game build, then update the server and all clients together. Updating the server early only moves the problem from the game to the mods.

Why does it say the server is full with only a few players on?

A player who crashed is still counted until their session times out. Wait a minute or two. If it persists, a clean restart clears it.

Is the Valheim server password case-sensitive?

Yes. It is matched exactly, including capitals and spaces. Retype it rather than pasting from a message, which may add a space at the end.

Why do I get disconnected every thirty minutes?

Thirty minutes is the default save interval. On a large world the save can stall the server long enough to drop players. Check whether the drops line up with World saved in the log.