114 Build Causes Repeated Disconnects

[DontMessWithDis]

Expected behavior

Players connecting into my Survival world.

Observed/Actual behavior

Players connect to the Hub and then attempt to connect to Survival, then get kicked with this error.

[14:47:22 INFO]: Averagestea98 lost connection: Internal Exception: io.netty.handler.codec.EncoderException: Packet too large: size 2203033 is over 8

Steps/models to reproduce

Update paper to the latest version build 114 on 1.21.5 and try to connect.

Plugin and Datapack List

No plugins installed I removed to make sure it wasn't a plugin issue, datapacks are terralith, structory, incendium, and alienend.

Paper version

This server is running Paper version 1.21.5-114-ver/1.21.5@a1b3058 (2025-06-18T10:59:02Z) (Implementing API version 1.21.5-R0.1-SNAPSHOT) You are running the latest version Previous version: 1.21.5-113-ba7fb23 (MC: 1.21.5)

Other

I have removed all plugins from my Survival server, and my proxy server with no luck. I can only assume that this is a paper related issue.

[electronicboy]

enable debug in server.properties, but, nothing really changed that would impact this sorta thing, that would likely scream that it was just a matter of bad timing and somebody did something to the world or their player containers

[DontMessWithDis]

We hadn't made any changes to the world prior to the issue arising.

[Q7Sa]

same issue same build even the one before 113, removed all plugins too and reset server settings

[mbax]

Try on latest 1.21.7, but also electronic's reply covers what to do: Enable debug in server.properties to get more info on disconnects.

[Q7Sa]

https://mclo.gs/DHkc2S0 latest paper with 1.21.7 and enabled debug

[Q7Sa]

I deleted the world which contains player data, basically a fresh server install + viaversion & viarewind

[Q7Sa]

'[22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException [22:07:55 WARN]: at io.netty.channel.AbstractChannel.close(ChannelPromise)(Unknown Source) [22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException [22:07:55 WARN]: at io.netty.channel.AbstractChannel.close(ChannelPromise)(Unknown Source) [22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException [22:07:55 WARN]: at io.netty.channel.AbstractChannel.close(ChannelPromise)(Unknown Source) [22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException [22:07:55 WARN]: at io.netty.channel.AbstractChannel.close(ChannelPromise)(Unknown Source) [22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException [22:07:55 WARN]: at io.netty.channel.AbstractChannel.close(ChannelPromise)(Unknown Source) [22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException [22:07:55 WARN]: at io.netty.channel.AbstractChannel.close(ChannelPromise)(Unknown Source) [22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException [22:07:55 WARN]: at io.netty.channel.AbstractChannel.close(ChannelPromise)(Unknown Source) [22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException [22:07:55 WARN]: at io.netty.channel.AbstractChannel.close(ChannelPromise)(Unknown Source) [22:07:55 WARN]: io.netty.channel.StacklessClosedChannelException'

Also I'm getting this spammed in console, it happened after log upload.

[electronicboy]

The log doesn't show the reported error, but, I think that due to the codec usage we don't really get told what packet is anymore, need to look into injecting that context back in; StacklessClosedChannelException generally means that something injected into the netty stack is broken and preventing the connection from actually closing

[Q7Sa]

is there any way I could help?

[Doc94]

Same error here with the "StacklessClosedChannelException" spam with a player disconnect. This server is running Paper version 1.21.7-26-main@533d93c (2025-07-12T19:13:10Z) (Implementing API version 1.21.7-R0.1-SNAPSHOT)