[1.12] critical exception handling a packet | players getting kicked from server

[Autissima]

I don’t know how to add steps to reproduce, because it strikes randomly, the server console giving out an exception:

[Netty Server IO #13/ERROR] [FML]: There was a critical exception handling a packet on channel effortlessbuilding
java.lang.NullPointerException: null

It affects nearly all players playing on the server, randomly kicking them, even without using effortlessbuilding at the time, is this some known incompatibility?

I’m grateful for any response

[Autissima]

In addition the server log gets spammed with this whenever someone gets kicked like that. It’s enough to clear the visible history in the terminal.

[12:29:29] [Netty Server IO #20/ERROR] [FML]: NetworkDispatcher exception
java.io.IOException: An established connection was aborted by the software in your host machine
        at sun.nio.ch.SocketDispatcher.writev0(Native Method) ~[?:1.8.0_291]
        at sun.nio.ch.SocketDispatcher.writev(Unknown Source) ~[?:1.8.0_291]
        at sun.nio.ch.IOUtil.write(Unknown Source) ~[?:1.8.0_291]
        at sun.nio.ch.SocketChannelImpl.write(Unknown Source) ~[?:1.8.0_291]
        at io.netty.channel.socket.nio.NioSocketChannel.doWrite(NioSocketChannel.java:432) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.AbstractChannel$AbstractUnsafe.flush0(AbstractChannel.java:856) [minecraft_server.1.12.2.jar:?]
        at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.forceFlush(AbstractNioChannel.java:368) [minecraft_server.1.12.2.jar:?]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:618) [minecraft_server.1.12.2.jar:?]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:559) [minecraft_server.1.12.2.jar:?]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:476) [minecraft_server.1.12.2.jar:?]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:438) [minecraft_server.1.12.2.jar:?]
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858) [minecraft_server.1.12.2.jar:?]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_291]

‌

[Requios]

Hmm this is difficult to fix without knowing what packet channel is causing the error. I see Unknown source in the log. Do the players locally also get an error log that maybe has more information?