Based on the log I can assume that this happened when one of my Ship entities loaded in the game. Of course though it doesn't tell me where the problem actually occurred >.<  . Any ideas for how I can fix this?

 

[16:44:43] [server thread/INFO] [FML]: Loading dimension 69 (BobVK) (net.minecraft.server.dedicated.DedicatedServer@79167c27)
[16:44:45] [Netty Epoll Server IO #6/ERROR] [FML]: NetworkDispatcher exception
java.lang.IllegalArgumentException: Payload may not be larger than 1048576 bytes
>       at net.minecraft.network.play.server.S3FPacketCustomPayload.<init>(S3FPacketCustomPayload.java:27) ~[gg.class:?]
>       at net.minecraftforge.fml.common.network.internal.FMLProxyPacket.toS3FPackets(FMLProxyPacket.java:136) ~[FMLProxyPacket.class:?]
>       at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.write(NetworkDispatcher.java:510) ~[NetworkDispatcher.class:?]
>       at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:658) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
>       at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:716) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
>       at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:706) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
>       at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:741) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
>       at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:895) ~[DefaultChannelPipeline.class:4.0.23.Final]
>       at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:240) ~[AbstractChannel.class:4.0.23.Final]
>       at net.minecraft.network.NetworkManager$4.run(NetworkManager.java:249) [ek$4.class:?]
>       at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:380) [singleThreadEventExecutor.class:4.0.23.Final]
>       at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:268) [EpollEventLoop.class:4.0.23.Final]
>       at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) [singleThreadEventExecutor$2.class:4.0.23.Final]
>       at java.lang.Thread.run(Thread.java:745) [?:1.8.0_77]
[16:44:45] [Netty Epoll Server IO #7/ERROR] [FML]: NetworkDispatcher exception
java.lang.IllegalArgumentException: Payload may not be larger than 1048576 bytes
>       at net.minecraft.network.play.server.S3FPacketCustomPayload.<init>(S3FPacketCustomPayload.java:27) ~[gg.class:?]
>       at net.minecraftforge.fml.common.network.internal.FMLProxyPacket.toS3FPackets(FMLProxyPacket.java:136) ~[FMLProxyPacket.class:?]
>       at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.write(NetworkDispatcher.java:510) ~[NetworkDispatcher.class:?]
>       at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:658) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
>       at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:716) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
>       at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:706) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
>       at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:741) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
>       at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:895) ~[DefaultChannelPipeline.class:4.0.23.Final]
>       at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:240) ~[AbstractChannel.class:4.0.23.Final]
>       at net.minecraft.network.NetworkManager$4.run(NetworkManager.java:249) [ek$4.class:?]
>       at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:380) [singleThreadEventExecutor.class:4.0.23.Final]
>       at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:268) [EpollEventLoop.class:4.0.23.Final]
>       at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) [singleThreadEventExecutor$2.class:4.0.23.Final]
>       at java.lang.Thread.run(Thread.java:745) [?:1.8.0_77]
[16:44:46] [server thread/INFO]: Monkey1357 lost connection: TranslatableComponent{key='disconnect.genericReason', args=[internal Exception: java.lang.IllegalArgumentException: Payload may not be larger than 1048576 bytes], siblings=[], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=null, hoverEvent=null, insertion=null}}

I suggest you set a breakpoint where the exception is thrown from the

S3FPacketCustomPayload

constructor.

 

If the packet is a wrapper for an

IMessage

, the

S3FPacketCustomPayload#channel

field will be the name of the

SimpleNetworkWrapper

that sent it and the first byte in the

S3FPacketCustomPayload#data

field (

ByteBuf#getByte

) should be the discriminator of the

IMessage

.

that is a lot of information for a single entity, like an absurd amount for a single entity. Are you sure everything that is being added to the packet is done correctly?

Im confused about what this means though. Does this mean that I tried sending an IMessage larger than 1MB? I don't use packets so this error doesnt make sense to me

Something you are sending is over 1MB, we don't know what due to how to things are designed, but as the others said you can use your IDE to track down what is being sent to see why the game things you need so much data.