Forge server kicking players randomly, sometimes unable to join

[Kull]

This is what happens when someone gets randomly kicked 

[23:12:03] [Netty Server IO #1/ERROR] [FML]: NetworkDispatcher exception
java.io.IOException: An existing connection was forcibly closed by the remote host
        at sun.nio.ch.SocketDispatcher.read0(Native Method) ~[?:1.8.0_231]
        at sun.nio.ch.SocketDispatcher.read(Unknown Source) ~[?:1.8.0_231]
        at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source) ~[?:1.8.0_231]
        at sun.nio.ch.IOUtil.read(Unknown Source) ~[?:1.8.0_231]
        at sun.nio.ch.SocketChannelImpl.read(Unknown Source) ~[?:1.8.0_231]
        at io.netty.buffer.PooledUnsafeDirectByteBuf.setBytes(PooledUnsafeDirectByteBuf.java:288) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1100) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.socket.nio.NioSocketChannel.doReadBytes(NioSocketChannel.java:372) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:123) [minecraft_server.1.12.2.jar:?]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:624) [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_231]

aaand when someone joins

[23:07:05] [Server thread/ERROR] [FML]: FMLIndexedMessageCodec exception caught
io.netty.handler.codec.EncoderException: java.lang.RuntimeException: Undefined discriminator for message type journeymap.common.network.DimensionPermissionPacket in channel jm_dim_permission
        at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:106) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:801) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:814) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:794) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:831) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1032) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:296) ~[minecraft_server.1.12.2.jar:?]
        at net.minecraftforge.fml.common.network.simpleimpl.SimpleNetworkWrapper.sendTo(SimpleNetworkWrapper.java:250) [SimpleNetworkWrapper.class:?]
        at journeymap.common.network.PacketHandler.sendDimensionPacketToPlayer(PacketHandler.java:57) [PacketHandler.class:1.12.2-5.5.3]
        at journeymap.server.events.ForgeEvents.on(ForgeEvents.java:73) [ForgeEvents.class:1.12.2-5.5.3]
        at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_1021_ForgeEvents_on_EntityJoinWorldEvent.invoke(.dynamic) [?:?]
        at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) [ASMEventHandler.class:?]
        at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182) [EventBus.class:?]
        at net.minecraft.world.World.func_72838_d(World.java:1206) [amu.class:?]
        at net.minecraft.world.WorldServer.func_72838_d(WorldServer.java:1058) [oo.class:?]
        at net.minecraft.server.management.PlayerList.func_72377_c(PlayerList.java:377) [pl.class:?]
        at net.minecraft.server.management.PlayerList.initializeConnectionToPlayer(PlayerList.java:166) [pl.class:?]
        at shadows.fastbench.net.HijackedDedicatedPlayerList.initializeConnectionToPlayer(HijackedDedicatedPlayerList.java:19) [HijackedDedicatedPlayerList.class:?]
        at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.completeServerSideConnection(NetworkDispatcher.java:255) [NetworkDispatcher.class:?]
        at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.access$100(NetworkDispatcher.java:72) [NetworkDispatcher.class:?]
        at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher$1.func_73660_a(NetworkDispatcher.java:205) [NetworkDispatcher$1.class:?]
        at net.minecraft.network.NetworkManager.func_74428_b(NetworkManager.java:285) [gw.class:?]
        at net.minecraft.network.NetworkSystem.func_151269_c(NetworkSystem.java:180) [oz.class:?]
        at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:790) [MinecraftServer.class:?]
        at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:397) [nz.class:?]
        at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?]
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_231]
Caused by: java.lang.RuntimeException: Undefined discriminator for message type journeymap.common.network.DimensionPermissionPacket in channel jm_dim_permission
        at net.minecraftforge.fml.common.network.FMLIndexedMessageToMessageCodec.encode(FMLIndexedMessageToMessageCodec.java:76) ~[FMLIndexedMessageToMessageCodec.class:?]
        at io.netty.handler.codec.MessageToMessageCodec$1.encode(MessageToMessageCodec.java:67) ~[minecraft_server.1.12.2.jar:?]
        at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88) ~[minecraft_server.1.12.2.jar:?]
        ... 29 more

included client-side log

 

edit: I've ran it with journey maps disabled and i still end up getting randomly dc'd

latest.log

Edited December 12, 2019 by Kull

[DavidM]

Please post the server log of when someone got kicked.