[22:02:06] [Server thread/ERROR] [FML]: FMLIndexedMessageCodec exception caught
io.netty.handler.codec.EncoderException: java.lang.RuntimeException: Undefined discriminator for message type toast.naturalAbsorption.network.MessageSyncShield in channel NA|CH1
at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:106) ~[MessageToMessageEncoder.class:?]
at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116) ~[MessageToMessageCodec.class:?]
at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:801) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:814) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:794) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:831) ~[AbstractChannelHandlerContext.class:?]
at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1032) ~[DefaultChannelPipeline.class:?]
at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:296) ~[AbstractChannel.class:?]
at net.minecraftforge.fml.common.network.simpleimpl.SimpleNetworkWrapper.sendTo(SimpleNetworkWrapper.java:250) [SimpleNetworkWrapper.class:?]
at toast.naturalAbsorption.EventHandler.onEntityJoinWorld(EventHandler.java:115) [EventHandler.class:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_704_EventHandler_onEntityJoinWorld_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:747) [EventBus.class:?]
at org.spongepowered.mod.event.SpongeToForgeEventFactory.createAndPostEntityJoinWorldEvent(SpongeToForgeEventFactory.java:576) [SpongeToForgeEventFactory.class:1.12.2-2768-7.1.5]
at org.spongepowered.mod.event.SpongeToForgeEventFactory.createAndPostForgeEvent(SpongeToForgeEventFactory.java:280) [SpongeToForgeEventFactory.class:1.12.2-2768-7.1.5]
at org.spongepowered.mod.event.SpongeModEventManager.post(SpongeModEventManager.java:338) [SpongeModEventManager.class:1.12.2-2768-7.1.5]
at org.spongepowered.mod.event.SpongeModEventManager.extendedPost(SpongeModEventManager.java:435) [SpongeModEventManager.class:1.12.2-2768-7.1.5]
at org.spongepowered.mod.event.SpongeModEventManager.post(SpongeModEventManager.java:404) [SpongeModEventManager.class:1.12.2-2768-7.1.5]
at org.spongepowered.common.event.SpongeEventManager.post(SpongeEventManager.java:465) [SpongeEventManager.class:1.12.2-2768-7.1.5]
at org.spongepowered.common.SpongeImpl.postEvent(SpongeImpl.java:242) [SpongeImpl.class:1.12.2-2768-7.1.5]
at org.spongepowered.common.event.tracking.PhaseTracker.spawnEntityWithCause(PhaseTracker.java:970) [PhaseTracker.class:1.12.2-2768-7.1.5]
at net.minecraft.world.WorldServer.spawnEntity(WorldServer.java:3134) [oo.class:?]
at net.minecraft.server.management.PlayerList.func_72368_a(PlayerList.java:1852) [pl.class:?]
at net.minecraft.network.NetHandlerPlayServer.func_147342_a(NetHandlerPlayServer.java:1119) [pa.class:?]
at net.minecraft.network.play.client.CPacketClientStatus.func_148833_a(SourceFile:31) [lb.class:?]
at net.minecraft.network.play.client.CPacketClientStatus.func_148833_a(SourceFile:8) [lb.class:?]
at org.spongepowered.common.event.tracking.phase.packet.PacketPhaseUtil.onProcessPacket(PacketPhaseUtil.java:193) [PacketPhaseUtil.class:1.12.2-2768-7.1.5]
at net.minecraft.network.PacketThreadUtil$1.redirect$onProcessPacket$zli000(SourceFile:539) [hv$1.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) [hv$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_201]
at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_201]
at net.minecraft.util.Util.func_181617_a(SourceFile:46) [h.class:?]
at org.spongepowered.common.SpongeImplHooks.onUtilRunTask(SpongeImplHooks.java:297) [SpongeImplHooks.class:1.12.2-2768-7.1.5]
at net.minecraft.server.MinecraftServer.redirect$onRun$zjm000(MinecraftServer.java:3963) [MinecraftServer.class:?]
at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:723) [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_201]
Caused by: java.lang.RuntimeException: Undefined discriminator for message type toast.naturalAbsorption.network.MessageSyncShield in channel NA|CH1
at net.minecraftforge.fml.common.network.FMLIndexedMessageToMessageCodec.encode(FMLIndexedMessageToMessageCodec.java:76) ~[FMLIndexedMessageToMessageCodec.class:?]
at io.netty.handler.codec.MessageToMessageCodec$1.encode(MessageToMessageCodec.java:67) ~[MessageToMessageCodec$1.class:?]
at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88) ~[MessageToMessageEncoder.class:?]
... 39 more

Duplicate of #4.