io.netty.handler.codec.DecoderException: The received string length is longer than maximum allowed (32 > 20)

[17:19:45] [Server thread/INFO]: HowardZHY[/127.0.0.1:55934] logged in with entity id 208 at (-111.5, 80.5, 206.5) [17:19:45] [Server thread/INFO]: HowardZHY joined the game [17:19:46] [Server thread/INFO]: HowardZHY lost connection: TextComponent{text='Disconnected', siblings=[], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=null, hoverEvent=null, insertion=null}} [17:19:46] [Server thread/INFO]: HowardZHY left the game

There's no error message in either server log or vanilla client log.

The error in Forge client is

[17:19:45] [Netty Client IO #3/ERROR] [FML/]: NetworkDispatcher exception io.netty.handler.codec.DecoderException: The received string length is longer than maximum allowed (32 > 20) at net.minecraft.network.PacketBuffer.func_150789_c(SourceFile:246) ~[em.class:?] at net.minecraft.network.play.server.S3FPacketCustomPayload.func_148837_a(S3FPacketCustomPayload.java:33) ~[gg.class:?] at net.minecraft.util.MessageDeserializer.decode(SourceFile:40) ~[en.class:?] at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:249) ~[ByteToMessageDecoder.class:4.0.23.Final] at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:149) ~[ByteToMessageDecoder.class:4.0.23.Final] ...