Players cannot connect to a Project Zomboid server
Updated 2026-11-05
When players cannot connect to a Project Zomboid server, it is nearly always one of five things. The player's game is on a different build from the server. A Workshop mod updated and the server has not restarted. The server's UDP ports, 16261 and 16262 by default, are not reachable from the internet. The Steam relay setting is getting in the way. Or the account, password or whitelist does not match. Start by asking the player what they see, because the message narrows it down fast.
What does the error tell me?
| The player sees | Look at first |
|---|---|
| Connection failed, or the server did not respond | Server offline, wrong IP or port, blocked ports |
| Sits on "Getting server info" | Server still starting, blocked ports, build mismatch, relay |
| A message about the server version | The player's build or version differs from the server |
| "Workshop item version is different than server's" | A mod updated, restart the server |
| Rejected for password, account or whitelist | Login details or whitelist |
"Getting server info" is the step the game was on when it gave up. It does not name a cause, so work through the sections below.
Is the server fully started?
A server with a long mod list has to download and load every mod before it accepts anyone. Players who try during that time wait and then fail. Watch the server console until it reports that the server has started, then try again.
Are the player and the server on the same build?
Since 29 July 2026, Build 42 is the default branch on Steam. Build 41 is the legacy41 branch. A game on one cannot join a server on the other, and the server browser hides servers from the other build entirely.
To check or change it, the player right clicks Project Zomboid in their Steam library, opens Properties, then Game Versions & Betas, and picks the same branch as the server. A friend who once tried a beta and forgot about it is a common case.
Matching branches can still differ by version, for example right after a patch. One side updates first and the other has to catch up. Since 42.21, a player on a different version gets a clear message saying so. A dedicated server picks up the new version when it is updated and restarted.
Is a Workshop mod out of date?
Steam updates a mod for players as soon as the author publishes. The server keeps its copy until it restarts. From that moment, everyone who tries to join is turned away with a mod version error. Restart the server and it downloads the new copy too. The longer the mod list, the more often this happens.
Are the ports open? (self hosting)
If the server runs at home, the router has to send game traffic to it. Project Zomboid uses UDP. Forwarding TCP does nothing.
| Port | Protocol | Name in the .ini |
|---|---|---|
| 16261 | UDP | DefaultPort |
| 16262 | UDP | UDPPort |
Forward both to the local IP of the PC running the server. If you changed the numbers in the .ini, forward the ones you chose. Then let the server through the firewall, either Windows Defender Firewall or ufw on Linux. The UPnP=true line asks the router to open ports on its own, but plenty of routers ignore it.
Two traps catch people here:
- Testing from inside. Many routers will not loop a connection back to their own public IP. The host should join with the local IP, or
127.0.0.1on the same PC. Friends outside use the public IP. - Shared public IP. Some internet providers put many homes behind one public address, known as CGNAT. Port forwarding cannot work there, whatever you set on the router.
Is Steam relay helping or hurting?
The join screen has a Use Steam Relay option. It sends the connection through Steam's network, which can get around a strict home network. It can also fail behind a VPN or a restrictive provider. Have the player try it both ways, with any VPN switched off.
Is the login right?
The first time someone joins, the username and password they type become their account on that server. Typing a different password next time fails, and a different username makes a new character. An admin can set a new password with setpassword "name" "newpassword" in the console.
On a whitelisted server, only existing accounts get in. An admin creates them with adduser "name" "password". Also check the join password, which is separate from the account password, and that the player is not banned.
The IP goes in the IP box and the port in the port box. Typing address:port into one field does not work. If the server moved, delete the saved entry and add it again.
Where are the logs?
The player's own log is console.txt in their Zomboid folder, %UserProfile%\Zomboid\console.txt on Windows or ~/Zomboid/console.txt elsewhere. The server keeps a log of the same name. Search either one for "version", "workshop", "whitelist" or "timeout".
On a server from this site
Our servers have their own address, so there is no router or port forwarding involved. The panel shows the IP and port to share. The join password and Whitelist only are settings in the panel, and the Add whitelisted account button makes accounts without typing commands. When a mod update locks players out, the Check mod updates button confirms it and a restart fixes it. If you want to stop fighting your router, see plans.