crash

[20:41:28] [Netty Server IO #2/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_221]
        at sun.nio.ch.SocketDispatcher.read(Unknown Source) ~[?:1.8.0_221]
        at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source) ~[?:1.8.0_221]
        at sun.nio.ch.IOUtil.read(Unknown Source) ~[?:1.8.0_221]
        at sun.nio.ch.SocketChannelImpl.read(Unknown Source) ~[?:1.8.0_221]
        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_221]
[20:41:28] [Server thread/INFO] [minecraft/NetHandlerPlayServer]: MagnificentKevin lost connection: Internal Exception: java.io.IOException: An existing connection was forcibly closed by the remote host
[20:41:28] [Server thread/INFO] [minecraft/DedicatedServer]: MagnificentKevin left the game