---
title: "Mismatched mod channel list, missing registry entries and other mod errors"
url: https://help.endercloud.in/docs/mod-mismatch-and-missing-mods-errors
category: "Minecraft Hosting › Troubleshooting & Performance"
type: Troubleshooting
tags: ["connection", "modpack", "mods", "troubleshooting"]
keywords: "mismatched mod channel list, connection closed - mismatched mod channel list, missing registry entries, fatally missing registry entries, failed to synchronize registry data, incomplete set of tags received from server. please contact server operator, channel of mod failed to connect, mod rejections, missing mods, forge, neoforge, fabric, modpack join error, can't join modded server, mod mismatch, mismatched mods, mods don't match, missing mods error, registry error, same mods client and server"
difficulty: intermediate
time: "10 minutes"
updated: 2026-11-14
source: Endercloud Knowledge Base (official)
---

# Mismatched mod channel list, missing registry entries and other mod errors

> These errors mean the player's mods don't match the server's. Install the exact same modpack, mod versions and loader version on both sides.

Errors such as `Mismatched mod channel list`, `Fatally missing registry entries`, `Failed to synchronize registry data` or `Incomplete set of tags received from server. Please contact server operator.` all mean the same thing: the mods on the player's game are not the same as the mods on the server. Modded Minecraft needs both sides to match closely.

## Why it happens

-   The player is missing a mod the server has (or has an extra one that must also be on the server).
    
-   A mod has a **different version** on the player's game and the server.
    
-   The **mod loader** is different: Forge vs NeoForge vs Fabric, or a different loader version.
    
-   The **modpack version** is different, for example the server was updated but players still have the old pack.
    
-   The player is trying to join with a plain (unmodded) game.
    

## How to fix it

1.  **Read the list in the error.** NeoForge and newer Forge versions often show which mod or channel is missing or mismatched. Fabric errors usually name the mod or registry. The server's `logs/latest.log` may say more: see [How to read logs](/docs/how-to-read-logs-and-crash-reports).
    
2.  **Using a modpack?** Have every player install the **same modpack and the same pack version** as the server, using CurseForge, Modrinth, Prism or the pack's own launcher. This is the easiest way to keep everything matched. If you installed the pack from the **Modpacks** tab, check which pack version you picked there and give players that exact version.
    
3.  **Using your own mod list?** Compare the server's `mods` folder (in **Files**, or **Mods** → **Manage Mods**) with the player's `mods` folder. Make the file names and versions match. Players may also have client-only mods (minimaps, shaders, performance mods) that the server doesn't need; those are normally fine.
    
4.  **Match the loader.** The server's software and version are shown at the top of the **Versions** tab. The player must use the same loader and the same Minecraft version, ideally the same loader version too.
    
5.  **Restart and try again.** After changing server mods, restart the server before testing.
    

> **Warning:**
> Removing a mod from the server that added blocks, items or mobs can delete those things from your world. Make a backup in **Backups** before removing mods from an existing world.

## Server-side only and client-side only mods

-   Some mods only run on the server (for example many admin or performance mods). Players don't need them.
    
-   Some mods only run on the player's game (shaders, minimaps, zoom). They must **not** be on the server, or it may fail to start. See [Server won't start](/docs/minecraft-server-wont-start).
    
-   Mods that add content (blocks, items, mobs, dimensions) must be on **both**, with the same version.
    

## Frequently asked questions

**Q: Can Java players without mods join my modded server?**

Usually not on Forge or NeoForge if the server has content mods. Some Fabric servers that only use server-side mods allow plain clients. ViaVersion does not help here.

**Q: Can Bedrock players join a modded server?**

Not with content mods installed. Bedrock players can't load Java mods.

**Q: Where do I find which mods the server has?**

Open **Mods** → **Manage Mods**, which lists installed mods, or look in the `mods` folder in **Files**. See [How to install mods](/docs/how-to-install-mods) and [How to install a modpack](/docs/how-to-install-a-modpack).