Connectivity Problem with Minecraft - Connection Lost when trying to connect to server

Technical Support
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1

System Information

Field Value
Operating System Linux - Ubuntu 24.04.2 on x86_64
Product AMP ‘Phobos’ v2.6.0.12 (Mainline)
Virtualization None
Application Minecraft
Module MinecraftModule
Running in Container No
Current State Ready

Problem Description

Issue

I have been trying to set up a server that uses the All of Fabric 7 modpack. When I set the server type to fabric, I am unsure of what fabric installer version to have selected as I download and play through the CurseForge Launcher app. Once I have that done, I drag the AOF7 server modpack zip into the instance file manager tab and extract it. When I initially did this, no new files appeared, such as the mods folder. I then tried making a new directory and after I made it, then the files appeared and I deleted the new directory folder. I started the server up wihtout any errors and launched minecraft and tried connecting to the server. I immediately get a connection lost screen with the following text:

Internal Exception: io.netty.handler.codec.DecoderException: io.netty.handler.codec.EncoderException: java.io.IOException: Root tag must be a named compound tag

Reproduction Steps

  • Create Instance
  • Set server type to fabric
  • Set Minecraft version to 1.20.1
  • Set fabric version to 0.16.0
  • Put the .zip file for server version of mod pack into the file manager
  • Extracted the files from .zip
  • Set ServerJAR to Fabric.JAR
  • Start up instance
  • Launch MC and try to join server
2

You’ll want to read the client and server logs, you might need to go to the modpack’s discord to see if it’s a common issue.

3

I checked the mod’s discord and didn’t seem to have anyone else report the issue. However, I restarted the server and tried connecting in order to get the logs, except this time i got two separate prompts. The First was: owo > handshake failure incompatible server.
The second was: Internal Exception: io.netty.handler.codec.DecoderException: net.mincraft.class_148: Loading NBT data

I also don’t really know what I’m looking at with the logs nor the best way to post them for others to examine.

edit: update,

I restarted both server and my game one more time and am back to receiving the initial text instead of the newer ones.

4

Make sure that you have all the correct server .jar files inside the mods folder