I am at my wit's end trying to figure out what keeps going wrong. Reading the error log tells me absolutely nothing I can understand, and after making a blank new server and finally having it work after so long, just to have it break again, is extremely irritating. I would love for someone to decipher what this error log says and point me in a direction, at least, so I'm not swinging blindly.

Minecraft 1.16.5 and Forge 36.2.2

 

[14:47:37] [Server thread/INFO] [minecraft/PlayerList]: Hyratos[/192.168.1.195:64650] logged in with entity id 45 at (481.30365299459726, 78.0, 426.6331819365098)
[14:47:37] [Server thread/INFO] [minecraft/DedicatedServer]: Hyratos joined the game
[14:47:37] [Netty Server IO #2/ERROR] [tconstruct/]: MaterialRecipeSerializer: Error reading recipe from packet
java.lang.NullPointerException: null
    at slimeknights.tconstruct.library.recipe.material.MaterialRecipeSerializer.writeSafe(MaterialRecipeSerializer.java:70) ~[tconstruct:1.16.5-3.1.1.252]
    at slimeknights.tconstruct.library.recipe.material.MaterialRecipeSerializer.writeSafe(MaterialRecipeSerializer.java:20) ~[tconstruct:1.16.5-3.1.1.252]
    at slimeknights.tconstruct.common.recipe.LoggingRecipeSerializer.func_199427_a_(LoggingRecipeSerializer.java:49) ~[tconstruct:1.16.5-3.1.1.252]
    at net.minecraft.network.play.server.SUpdateRecipesPacket.func_218771_a(SourceFile:64) ~[?:?]
    at net.minecraft.network.play.server.SUpdateRecipesPacket.func_148840_b(SourceFile:43) ~[?:?]
    at net.minecraftforge.network.VanillaPacketSplitter.appendPackets(VanillaPacketSplitter.java:100) ~[forge:?]
    at net.minecraftforge.network.ForgeConnectionNetworkFilter.splitPacket(ForgeConnectionNetworkFilter.java:85) ~[forge:?]
    at net.minecraftforge.network.VanillaPacketFilter.encode(VanillaPacketFilter.java:75) ~[forge:?]
    at net.minecraftforge.network.VanillaPacketFilter.encode(VanillaPacketFilter.java:38) ~[forge:?]
    at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88) ~[server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738) ~[server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:801) ~[server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:814) ~[server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:794) ~[server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:831) ~[server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1071) ~[server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:300) ~[server-1.16.5-20210115.111550-extra.jar:?]
    at net.minecraft.network.NetworkManager.lambda$sendPacket$5(NetworkManager.java:196) ~[?:?]
    at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163) [server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404) [server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:465) [server-1.16.5-20210115.111550-extra.jar:?]
    at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) [server-1.16.5-20210115.111550-extra.jar:?]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_301]
[14:47:38] [Server thread/WARN] [Mekanism/]: Failed to retrieve username for UUID 594cf1d3-7a0c-4e6f-bd16-5df4bb7ce72b, you might want to add it to the JSON cache
[14:47:38] [Server thread/WARN] [minecraft/EntityDataManager]: defineId called for: class dev.itsmeow.whisperwoods.entity.EntityMoth from class dev.itsmeow.whisperwoods.imdlib.entity.EntityTypeContainer
[14:47:38] [Server thread/WARN] [minecraft/EntityDataManager]: defineId called for: class dev.itsmeow.whisperwoods.entity.EntityMoth from class dev.itsmeow.whisperwoods.imdlib.entity.util.EntityTypeContainerContainable
[14:47:38] [Server thread/WARN] [minecraft/EntityDataManager]: defineId called for: class its_meow.betteranimalsplus.common.entity.EntityButterfly from class dev.itsmeow.betteranimalsplus.imdlib.entity.EntityTypeContainer
[14:47:38] [Server thread/WARN] [minecraft/EntityDataManager]: defineId called for: class its_meow.betteranimalsplus.common.entity.EntityButterfly from class dev.itsmeow.betteranimalsplus.imdlib.entity.util.EntityTypeContainerContainable
[14:47:38] [Server thread/WARN] [minecraft/EntityDataManager]: defineId called for: class dev.itsmeow.whisperwoods.entity.EntityZotzpyre from class dev.itsmeow.whisperwoods.imdlib.entity.EntityTypeContainer
[14:47:38] [Server thread/INFO] [survive/]: Syncing Armor Data To Client (Hyratos)
[14:47:38] [Server thread/INFO] [minecraft/ServerPlayNetHandler]: Hyratos lost connection: Internal Exception: io.netty.handler.codec.EncoderException: java.lang.NullPointerException
[14:47:38] [Server thread/INFO] [minecraft/DedicatedServer]: Hyratos left the game
 

Edited September 17, 20214 yr by Hyratos

error in Tinkers Construct, check if you use the latest version of the mod.
if you use the latest version report the bug to the mod author else try with the latest version