---
title: "Terraria \"Lost Connection\": Causes and Fixes on a Server"
description: "Terraria \"Lost connection\" on a server: read the last loading line, then check server status, versions, anti-cheat kicks, port and server type."
url: "https://www.gameserverkings.com/knowledge-base/terraria/terraria-lost-connection/"
category: "Terraria"
category_url: "https://www.gameserverkings.com/knowledge-base/terraria/"
published: "2026-10-28T03:26:04.686Z"
updated: "2026-10-28T03:26:04.686Z"
source_format: "markdown"
site: "GameServerKings"
---

# Terraria "Lost Connection": Causes and Fixes on a Server

"Lost connection" in Terraria means the game's network link to the world dropped, either while you were joining or partway through a session. On a dedicated server there are four usual causes: the server stopped or crashed, the client and server are on different versions, the built-in anti-cheat kicked you, or the player is on a different kind of server than they think (vanilla, TShock or tModLoader). The loading text you saw just before the message tells you which one to check first.

We run Terraria servers every day, and this guide is written from the server side. Everything below applies to a vanilla Terraria dedicated server, and the notes on TShock and tModLoader cover what changes with those.

> [!NOTE] Checked against Terraria **1.4.5.8**
> terraria.org listed `terraria-server-1458.zip` as the current dedicated server on 28 October 2026. The game strings quoted here come from Terraria's English text data.

## Read the Last Message Before "Lost connection"

A Terraria client works through a fixed set of status lines when it joins a server: **Found server**, **Sending player data...**, **Requesting world information** and **Requesting tile data**. The line you saw last before "Lost connection" narrows the cause down:

| Last thing on screen | What it usually means | Check first |
|---|---|---|
| Still connecting, or "Connection timed out" | Nothing answered at that address | IP and port (see below) |
| **Found server**, then "Lost connection" | The server answered, then dropped you during the handshake | Versions, password, server type |
| **Requesting world information** or **Requesting tile data**, then "Lost connection" | You got through the handshake and dropped while the world was loading | Server console, then your connection |
| In the world, then "Lost connection" mid-game | The server stopped, or you were kicked | Server console |

If a different message appears, it is not this error and it has a clearer fix:

- `You are not using the same version as this server.` is a version mismatch. See step 2 below.
- `Incorrect password` means the password is wrong. It is set on the **Startup** tab, not in the console (see below).
- `You are banned from this server.` and `Kicked from server.` are moderation actions, not network faults.
- `This server is full right now, please try again later.` means the server is at its **Max Players** limit.

## 1. Check the Server Is Actually Running

Every player gets "Lost connection" at the same moment when the server process stops. Open the panel **Console** before you change anything on a player's PC.

- **Is it online?** The server is ready once the console prints `Listening on port` and `Type 'help' for a list of commands`. Until then, joins fail.
- **Did it crash or restart?** Scroll up in the console. A stack trace, or the server booting again, tells you it went down. Restore the world from the **Backups** tab if a crash keeps happening on load. [Maintaining your Terraria server](/knowledge-base/terraria/maintaining-your-server/) covers backups and the `.bak` file.
- **Did one player drop, or everyone?** When a single client drops, the server console logs a line ending in `lost connection...` and keeps running. That points at that player's connection or client, not at the server.

## 2. The Versions Do Not Match

The client and the server must run the same Terraria version. A mismatch usually shows `You are not using the same version as this server.`, but a player who is part-way through a Steam update can also get dropped during the handshake.

On our Terraria servers the **Terraria Version** variable on the Startup tab defaults to `latest`. The newest build only installs when you **reinstall**, though, so a server can sit on an older build after a Terraria patch while every Steam client has already updated. If players cannot connect right after a patch:

1. Make sure **Terraria Version** is `latest`, or set it to the exact build your players run (for example `1458` for 1.4.5.8).
2. Click **Reinstall Server** on the Settings tab. Worlds are not touched.
3. Start the server and have everyone restart Steam so their client is current too.

If you pin an older version so a plugin keeps working, every player has to be on that same build. [Maintaining your Terraria server](/knowledge-base/terraria/maintaining-your-server/) explains pinning.

The 1.4.5.0 update notes also list "Fixed a rare 'Lost connection' issue for slower clients". If either side is still on a 1.4.4 build, updating both is worth doing before you go any further.

## 3. Anti-Cheat Kicked the Player

The vanilla server has its own cheat protection, the `secure` setting. On our servers it is the **Anticheat** variable on the Startup tab, and it is **on (`1`) by default**. When it trips, the server drops the player and gives one of these reasons:

- `Cheating attempt detected: Projectile spam`
- `Cheating attempt detected: Add tile spam`
- `Cheating attempt detected: Remove tile spam`
- `Cheating attempt detected: Liquid spam`
- `Cheating attempt detected: Invalid kick-out`

Normal play can trigger these. Fast building or digging with a high-speed tool, a modded client or an auto-clicker, or dumping a lot of liquid at once can all set them off. If one player keeps dropping while placing or mining blocks, that is the pattern to look for.

To test it, set **Anticheat** to `0`, save, and restart. The panel rewrites `serverconfig.txt` from the Startup variables every time the server starts, so change the variable rather than editing `secure=` in the file. If the drops stop, you have a choice: leave anti-cheat off for a trusted group, or turn it back on and find out what that player is doing.

## 4. Wrong Address, Port or Server Type

**Use the panel's port, not 7777.** Terraria's default port is 7777, but the panel gives every server its own port and writes it into the server config at each start. Type the IP and port from **Address** at the top of the panel, and put the port in the separate port prompt under **Multiplayer → Join via IP**. The `port` [console command](/knowledge-base/terraria/terraria-server-commands/) prints the port the server actually bound to.

**There is no Steam join for a hosted server.** "Join via Steam" is for Host & Play worlds. Our standard Terraria server does not start with Terraria's `-steam` option, so everyone joins by IP. [Terraria multiplayer](/knowledge-base/terraria/terraria-multiplayer/) walks through both routes.

**Vanilla, TShock and tModLoader do not mix.**

- A **tModLoader** server needs every player on tModLoader, with the same tModLoader version and the same mods. A vanilla client cannot join it. See [How to mod Terraria with tModLoader](/knowledge-base/terraria/how-to-install-tmodloader/).
- A **TShock** server accepts vanilla clients of the matching Terraria version. TShock adds its own kicks and bans on top, so check the server console for a TShock reason before you blame the network. See [How to install TShock](/knowledge-base/terraria/tshock/).

**Journey characters only join Journey worlds.** A Classic, Expert or Master character cannot enter a Journey world, and the reverse is also true. If only some players are dropped at the same point every time, check which mode their characters were made in. [Terraria multiplayer](/knowledge-base/terraria/terraria-multiplayer/) covers this.

## 5. When It Is the Player's Connection

If the server is up, the versions match, nothing in the console shows a kick, and only one player keeps dropping, the problem is on their side:

- Restart the game and Steam, then verify the game files in Steam (**Properties → Installed Files → Verify integrity of game files**).
- Allow Terraria through their firewall or antivirus. Terraria's wiki lists a firewall blocking the game or its port as a standard reason people cannot connect.
- Try a wired connection, or switch off a VPN, if they drop mid-game rather than while joining.

You do not need to forward ports to join a hosted server. Port forwarding only matters if you run the server on your own PC at home.

## Common Questions

### Why does Terraria say "Lost connection" right after "Found server"?

The server answered and then dropped the connection during the handshake. Check versions first, then the server type (tModLoader versus vanilla), then the console for an anti-cheat or TShock kick.

### How do I fix "Lost connection" for just one player?

Look in the server console for a line ending in `lost connection...` and any kick reason near it. If you find a `Cheating attempt detected` reason, try **Anticheat** = `0`. If there is no reason, check that player's game version, their firewall, and whether their character is in Journey mode.

### Can a world file cause "Lost connection"?

A world that crashes the server when it loads drops everyone, and the console shows the crash. Restore a backup, or rename the `.bak` file Terraria keeps next to the world. [Maintaining your Terraria server](/knowledge-base/terraria/maintaining-your-server/) has the steps.

### Does port forwarding fix "Lost connection"?

Only when you host the server yourself. A hosted server is already reachable, so use the IP and port from the panel exactly as they are shown. On a rented [Terraria server](/games/terraria-server-hosting/), port forwarding does nothing.

## What to Read Next

- [Terraria Multiplayer: How to Play With Friends](/knowledge-base/terraria/terraria-multiplayer/) covers Steam versus IP joins, and the Journey Mode trap
- [Maintaining your Terraria server](/knowledge-base/terraria/maintaining-your-server/) covers version pinning, backups and world restores
- [Terraria server commands](/knowledge-base/terraria/terraria-server-commands/) lists `port`, `kick`, `ban` and the other console tools
- [Getting started with your Terraria server](/knowledge-base/terraria/getting-started-with-your-server/) lists every Startup variable, including Anticheat and Password

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