Description

When joining my neoforge server I'm getting an Internal Exception: java.net.SocketException: Connection reset error. The server boots and runs seemingly fine, but players cannot join. Github Gists of my client and server included in this issue.

Removing LuckPerms fixes this error and allows players to join.

Any fix would be greatly appreciated! <3

Reproduction Steps

Attempt to join 1.21.1 Neoforge 21.1.139 server with LuckPerms and included modlist installed

Expected Behaviour

Successful server connect

Server Details

neoforge 21.1.139 (MC: 1.21.1)

LuckPerms Version

v5.4.140

Logs and Configs

Client - https://gist.github.com/Meggle1/1d0af6e6ccd8e88ef440b4ca0ae3a760
Server - https://gist.github.com/Meggle1/02cf42169a0d546525cb014840238ab4

Extra Details

No response

Dealing with this same issue; No response regarding it for the past 3 weeks

Been having this issue too with no idea on how to fix it.

Same issue

Same Issue on my Modrinth Server install, using Neoforge 21.1.179

Logs are similar to @Meggle1's

Adding my mod list if it can help :

this is fixed in newer versions of LP

Is there no plan to fix this for 1.21.1 since its "fixed" in newer versions? This is still happening on 1.21.1 luckperms 5.4.10

Yeah, considering 1.21.1 is still a major version for people to use with such a critical issue on an insanely useful tool it'd be nice for it to be revisited with a fix.

Doesn't seem like it's gonna happen. Quote from bntfryingpan in discord, also known as Leah, a moderator on the Luckperms discord: "you can always backport a fix yourself. maintaining support for multiple minecraft versions for every platform is not really feasible. the only platform LP supports multiple versions for is bukkit but thats because its a (relatively) stable api"

Version 5.4.150 for 1.21.5 seems to fix the issue and works on 1.21.1. Hope this helps someone.

Has 1.21.5 on a 1.21.1 server been tested?

Has 1.21.5 on a 1.21.1 server been tested?

Works for me

Receiving the following crash when attempting to use v5.4.150:

---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 2025-06-23 13:10:17
Description: Exception in server tick loop

java.lang.NoSuchMethodError: 'net.minecraft.class_2168 net.minecraft.class_3222.method_64396()'
at knot//me.lucko.fabric.api.permissions.v0.Util.commandSourceFromEntity(Util.java:38)
at knot//me.lucko.fabric.api.permissions.v0.Options.get(Options.java:178)
at knot//net.minecraft.class_3324.handler$dam000$melius-vanish$vanish_vanishOnJoin(class_3324.java:11015)
at knot//net.minecraft.class_3324.method_14570(class_3324.java:206)
at knot//net.minecraft.class_8610.mixinextras$bridge$method_14570$38(class_8610.java)
at knot//net.minecraft.class_8610.wrapOperation$dki000$polymer-networking$polymerNet$prePlayHandshakeHackfest(class_8610.java:1038)
at knot//net.minecraft.class_8610.method_52408(class_8610.java:152)
at knot//net.minecraft.class_8736.method_53043(class_8736.java:22)
at knot//net.minecraft.class_8736.method_11054(class_8736.java:8)
at knot//net.minecraft.class_2600.method_11072(class_2600.java:27)
at knot//net.minecraft.class_3738.run(class_3738.java:18)
at knot//net.minecraft.class_1255.method_18859(class_1255.java:162)
at knot//net.minecraft.class_4093.method_18859(class_4093.java:23)
at knot//net.minecraft.server.MinecraftServer.method_24306(MinecraftServer.java:864)
at knot//net.minecraft.server.MinecraftServer.method_18859(MinecraftServer.java:173)
at knot//net.minecraft.class_1255.method_16075(class_1255.java:136)
at knot//net.minecraft.server.MinecraftServer.method_20415(MinecraftServer.java:846)
at knot//net.minecraft.server.MinecraftServer.method_16075(MinecraftServer.java:840)
at knot//net.minecraft.class_1255.method_18857(class_1255.java:145)
at knot//net.minecraft.server.MinecraftServer.method_18857(MinecraftServer.java:810)
at knot//net.minecraft.server.MinecraftServer.method_16208(MinecraftServer.java:815)
at knot//net.minecraft.server.MinecraftServer.method_29741(MinecraftServer.java:702)
at knot//net.minecraft.server.MinecraftServer.method_29739(MinecraftServer.java:281)
at java.base/java.lang.Thread.run(Thread.java:1583)

A detailed walkthrough of the error, its code path and all known details is as follows:

Receiving the following crash when attempting to use v5.4.150:

That's strange. No idea why it would work for us then
We used this one. https://www.curseforge.com/minecraft/mc-mods/luckperms/files/5971552