RimWorld Together Can't Connect to Server: Every Cause and Fix

When RimWorld Together will not let you join, the server is telling you why: the server console prints a line such as [Version mismatch], [Mod mismatch] or [Mod order mismatch] the moment a player is turned away. The most common causes are a different RimWorld Together version from the server, a mod list or load order that does not match the server's rules, the wrong password for a username that already exists, and port 25555 forwarded as UDP instead of TCP. Find the matching line below and apply the fix.

Start with the server console

Every RimWorld Together server logs connection attempts. Ask whoever runs it to watch the console while you try to join, or look yourself if it is yours.

The version must match exactly

The server compares the version number your mod sends with its own build and rejects anything that is not identical. Not close, identical. RimWorld Together releases often, with versions named by date such as 26.10.4.1, and Steam updates the Workshop mod for players automatically while servers stay on whatever was installed.

1. Check your version at the top left of RimWorld's main menu with the mod enabled.
2. Check the server's with the getversion command in its console.
3. Make them match. Usually the server should be updated to the newest release from the mod's GitHub releases.

If the group wants to stay on an older server build, every player needs the matching mod build instead. Each GitHub release includes the mod as 3005289691.zip (the Workshop ID), which can replace the Workshop copy, but Steam will try to update it again, so updating the server is far less hassle.

Updating the server can change save formats, so back up first. Our guide to backing up and updating a RimWorld Together server covers the safe order.

Mod mismatch: missing or extra mods

The server keeps a list in Configs/ModConfig.json. Each mod is Required or Optional. You are turned away if:

• you are missing any Required mod, or
• you are running any mod that is on neither list.

The second rule is the one that catches people. A harmless client mod like a UI tweak or a texture pack still gets you rejected unless the admin added it as Optional. DLCs such as Biotech, Ideology or Odyssey count as mods too, so a player without a Required DLC cannot join.

Fix it by asking the admin for the list. In the server console, modlist prints it. If the server set SteamWorkshopURL in ServerConfig.json, that collection has the mods in one place. Newer releases are also rolling out automatic mod download when you join, so on current builds the game may offer to fetch what is missing.

Harmony must be enabled and loaded above RimWorld Together. Without it the mod does not work at all.

Mod order and mod settings

If [Mod order mismatch] appears, you have the right mods in the wrong order. Load order matters in RimWorld, so the server enforces it. Sort your list in the mod manager to match the server's exactly.

[Mod config mismatch] only appears when the server has EnforceSettings turned on in ModConfig.json. It means a Required mod's own settings differ from the server's. The admin can share their mod settings files from RimWorld's config folder, or turn EnforceSettings off if exact settings do not matter to the group.

Why can the admin join when nobody else can?

This confuses a lot of new hosts. Admins (players made admin with op) skip all the mod checks. So you can test your own server, get in fine, and tell everyone it works, while every friend gets rejected for mods. The checks also do not run until a planet exists.

Test with a non admin account, or watch the console while a friend tries.

Wrong username or password

RimWorld Together accounts belong to each server. The first time you join, the username and password you type register an account on that server. After that, the same username needs the same password.

If someone else already registered your usual name, or you forgot your password, the server rejects the login. Try a different username. If it is your colony on the line, the admin can find your account in Assets/Users. There is no password reset command, so ask before anything is deleted.

The join password is a separate thing. If the server has one set in PasswordConfig.json or with setpassword, you are asked for it before the login, and a wrong one also gets you turned away.

The server is full or still creating the planet

Two quieter rejections:

• Full. The server turns players away once MaxPlayers in ServerConfig.json is reached. The default is 100, but a host may have set it lower.
• No planet yet. On a brand new server, the first player to join generates the planet. While that is happening, the server turns everyone else away. Wait for the first player to finish and settle, then join.

Nothing reaches the server

If the console shows nothing when you click connect, the problem is the network.

1. Two boxes. The connect screen has separate fields for IP and port. Put only the IP in the first box and only the port in the second, with no spaces.
2. TCP, not UDP. The server listens on TCP, port 25555 by default. Forwarding UDP out of habit is the most common home hosting mistake. Forward TCP and allow it through the firewall on the server PC.
3. IP binding. IP in ServerConfig.json should be 0.0.0.0 so the server listens on every network card.
4. Testing from the host PC. Many routers cannot loop back to their own public IP. The host should connect with 127.0.0.1 while friends use the public IP.
5. The right public IP. Some home connections sit behind carrier grade NAT and cannot be reached from outside at all, port forward or not. Our guide to hosting without port forwarding explains how to tell.

The full router walkthrough is in our port forwarding guide.

When the host is the problem

Many groups end up here because the server lives on one player's PC: it goes to sleep, the router changes, or nobody updated it after the last release. A RimWorld Together server from GamezServers removes the network half of this page. It has its own address with the port already open, stays online for the whole group, and the Version setting in the panel lets you pick the latest release or a specific tag so the server matches what your players run. The console shows every connection line from the table above, and ModConfig.json is in the browser file manager. Plans start at 2 GB, and the group can split the bill.

FAQ

Why does RimWorld Together say version mismatch?

Your mod and the server are on different builds, and they must match exactly. Compare the version on your main menu with the server's getversion output and update whichever is older.

What port does RimWorld Together use?

TCP 25555 by default, set with Port in ServerConfig.json. It must be forwarded as TCP.

Why can I join my own server but my friends cannot?

You are probably admin, and admins skip the mod checks. Your friends are being rejected for mods. Check the console for a mod mismatch line when they try.

Do I need the same DLCs as the server?

If the server lists a DLC as Required, yes. DLCs are checked like any other mod.

Can I join with extra client side mods?

Only if the admin lists them as Optional in ModConfig.json. Any mod that is on neither list gets you rejected.