Schedule 1 Can't Connect to Dedicated Server? Every Fix (2026)

When Schedule 1 can't connect to a dedicated server, the cause is nearly always one of a handful of things: the client mod is missing or outdated, the game and server are on different versions, the address went into the wrong fields, or the server is not actually running. Schedule I has no official dedicated servers, so every server runs the S1DedicatedServers (S1DS) mod, and every player needs its matching client mod. The fixes below are in order of how often they solve it.

Quick fix

1. Check the main menu has a Servers button. If not, the client mod is not installed. Follow how to join a Schedule 1 dedicated server.
2. Download the client mod again from the latest release link and extract it over the old one. Ask the server owner to update the server.
3. Use Servers, Direct Connect, with the IP and the port in their separate fields.
4. Make sure the server is online and has finished starting.
5. Keep Steam open and signed in. You must own Schedule I on Steam.
6. Match the runtime: normal Steam version with the IL2CPP client, alternate beta with the Mono client.

1. The client mod is not installed or not loading

You cannot join a Schedule 1 dedicated server with the unmodded game. Every player needs MelonLoader plus the S1DS client mod in the game folder. If there is no Servers button on the main menu, the mod is not loading.

• version.dll, the MelonLoader folder and the Mods folder must sit directly next to Schedule I.exe. Open the folder from Steam with Manage, Browse local files.
• The zip contents must not be inside an extra folder such as Il2cpp_Client\.
• It has to be a Client zip. Server zips are for the machine running the server.
• Avoid MelonLoader 0.7.1. Supported versions are 0.6.x, 0.7.0 and 0.7.2 or newer.

The full install, step by step, is in our join guide.

2. Version mismatch after a Schedule I update

This is the most common reason a server that worked yesterday stops working today. The server and every client must use matching Schedule I builds, and the client mod should match the server mod.

When Schedule I updates on Steam, your game updates straight away. The server does not, and the mod sometimes needs a new release to catch up with the game.

Players:

1. Start the game once and let MelonLoader regenerate. The first launch after an update takes a few extra minutes.
2. Download the client mod again from the latest release and extract it over the old files: Il2cpp_Client.zip or Mono-Client.zip.

Server owners: update the game and the server mod on the server. On GamezServers, press Update game in Settings. It installs the newest Schedule I and the newest server mod, and your world is backed up first and kept. Right after a big game patch, the mod or MelonLoader may need some time to catch up. Check the S1DS releases page for a new version.

3. The address is in the wrong fields

The Direct Connect panel has separate IP and Port fields. An address like 203.0.113.10:25600 splits into:

Pasting the whole address into the IP field, or leaving the port on a default when the server uses a different one, will fail. Copy the address fresh from the server's invite page or panel rather than from an old message.

4. Wrong runtime: IL2CPP vs Mono

Schedule I comes in two runtimes. The normal Steam version is IL2CPP. The Steam beta branch called alternate is Mono. The server and every player must use the same one.

To switch branch, right click Schedule I in Steam, Properties, Betas. On GamezServers, the server type is shown as Normal version or Mono version, and the invite page gives the right downloads. Only install one client DLL, never both.

5. The server is offline or still starting

• Still booting. The server runs the entire game, so it takes a while to start. The very first boot of a new server takes several minutes. Wait until it shows online.
• Asleep. On GamezServers, Sleep when empty stops the server after 90 minutes with nobody online. Anyone with access to the server starts it again in one click. Friends without access ask the owner.
• Crashed or stopped. The owner can check the Console tab for errors and press Restart.

The invite page shows whether the server is online right now, which saves a lot of guessing.

6. Steam sign in fails or times out

By default, S1DS servers check every player through Steam before they can join. That means:

• You must own Schedule I on Steam.
• Steam must be running and signed in on your PC.
• Joining through a VPN or a very slow connection can push the check past its time limit.

If you connect and then get dropped after a short delay, that is often this check timing out rather than a network failure. The server's authTimeoutSeconds defaults to 30 seconds, and the mod's docs recommend 60 for public servers and slower players. Self hosters can raise it in server_config.toml:

[authentication]
authProvider = 'SteamGameServer'
authTimeoutSeconds = 60

7. You were kicked or banned

If the server disconnects you straight after the Steam check, ask the owner whether you are banned. Owners remove a ban with unban <steamid> in the console, using your Steam ID. See Schedule 1 dedicated server commands.

8. A client mod is blocked

After the Steam check, the server verifies your installed client mods. By default it blocks known risky client mods, and owners can deny specific ones. If verification fails, the server disconnects you with a reason.

Move other mods out of your Mods folder, keep only the S1DS client, and try again. If you join fine, add your other mods back one at a time to find the blocked one.

9. The server is full, or you are banned

• Full. Every server has a player limit. On GamezServers it follows the plan: 4, 8 or 16 players. If you need more room, see Schedule 1 multiplayer with more than 4 players.
• Banned. Banned players are rejected at the Steam check. An operator can run unban <steamid> with your SteamID64. See Schedule 1 dedicated server commands.

10. Cannot see the server in the Public tab

The Public tab only lists servers whose owners opted into the public server list, which is off by default and needs a listing credential from the S1DS server portal. A server missing from Public can still be joined by IP and port. Use Direct Connect, then Add Server to save it to Favorites so it is one click next time.

If a server appears but shows no status, or cannot be added to favorites, its TCP status query is not reachable. That is a port issue on the server side, covered next.

11. Self hosted: ports, firewall and CGNAT

If you run the server yourself and friends outside your house cannot connect, check the ports. On a GamezServers server this is all done for you, so skip this section.

• Forward serverPort for both UDP and TCP. The mod's docs say the most common cause of a server that joins directly but never answers status queries is forwarding only UDP.
• Forward 27016 UDP for the Steam check.
• Allow the same ports through Windows Firewall.
• Friends outside your network use your public IP. Players on the same network use the local one, such as 192.168.1.50.
• If your router's WAN IP differs from your public IP, your provider uses CGNAT and port forwarding will not work.
• Running the server and playing on the same PC? Start the normal Schedule I client first, then the server. Steam may block the client if the server is already running.

Our port forwarding guide covers the router side, and the full self hosted setup is in how to make a Schedule 1 dedicated server.

12. The game crashes when you connect

• Make sure your client matches the server version, see fix 2.
• Remove other mods and try with only the S1DS client.
• Replace MelonLoader 0.7.1 if you have it.
• After a game update, let the first launch finish so MelonLoader regenerates its files before you connect.

Connecting to a GamezServers server

On a hosted server there are no ports, firewalls or routers to fix. If you cannot join:

1. Open the server's invite link and check it shows online.
2. Follow the setup steps on that page, with the download buttons for that server's type.
3. Copy the address from the page and split it into IP and Port in Direct Connect.
4. If the game updated recently, the owner presses Update game and everyone downloads the client mod again.

FAQ

Why can't I connect to a Schedule 1 dedicated server?

Usually the client mod is missing or outdated, your game and the server are on different versions, or the IP and port were typed into the wrong fields. Reinstall the latest client mod and use Direct Connect with the IP and port separately.

Why is there no Servers button in Schedule 1?

The S1DS client mod is not loading. version.dll, MelonLoader and Mods must be directly next to Schedule I.exe.

Why can't I see the server in the server list?

The Public tab only shows servers that opted in. Join private servers with Direct Connect, then save them with Add Server.

Why do I get kicked a few seconds after joining?

Usually the Steam check timing out, a blocked client mod, or a version mismatch. Keep Steam signed in, remove other mods, and update the client mod.

Can I join without owning Schedule I on Steam?

No. Servers check every player through Steam by default, so you need your own copy with Steam running.