[1.11.2] Weird Packet Error

I'm sending a packet to everyone on the server from my Item's onItemUse method.

It looks like this:

@Override
	public EnumActionResult onItemUse(EntityPlayer player, World world, BlockPos pos, EnumHand hand, EnumFacing facing, float hitX, float hitY, float hitZ)
	{
		ItemStack stack = player.getHeldItem(hand);
		Block block = world.getBlockState(pos).getBlock();

		if (hasEntityData(stack))
		{
			BlockPos finalPos = pos;

			if (!block.isReplaceable(world, pos))
			{
				finalPos = pos.offset(facing);
			}

			Entity entity = getEntity(stack, world);
			if (entity != null)
			{
				if (!world.isRemote)
				{
					entity.setPositionAndRotation(finalPos.getX() + 0.5, finalPos.getY(), finalPos.getZ() + 0.5, 180 + player.rotationYawHead, 0.0f);
					world.spawnEntity(entity);
					if (entity instanceof EntityLiving)
					{
						((EntityLiving) entity).playLivingSound();
					}
					clearEntityData(stack);
					player.setHeldItem(hand, ItemStack.EMPTY);
				}
				player.getEntityData().removeTag("overrideKey");
				Pickup.network.sendToAll(new CarrySlotPacket(9, player.getEntityId()));
				return EnumActionResult.SUCCESS;
			}
		}

		return EnumActionResult.FAIL;
	}

The packet is not either not sent or recieved correctly, I'm getting this error:

[16:17:57] [Client thread/ERROR] [FML]: SimpleChannelHandlerWrapper exception
java.lang.NullPointerException
	at net.minecraftforge.fml.common.network.FMLOutboundHandler$OutboundTarget$5.selectNetworks(FMLOutboundHandler.java:154) ~[FMLOutboundHandler$OutboundTarget$5.class:?]
	at net.minecraftforge.fml.common.network.FMLOutboundHandler.write(FMLOutboundHandler.java:297) ~[FMLOutboundHandler.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.write(AbstractChannelHandlerContext.java:651) ~[AbstractChannelHandlerContext.class:4.0.23.Final]
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:112) ~[MessageToMessageEncoder.class:4.0.23.Final]
	at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116) ~[MessageToMessageCodec.class:4.0.23.Final]
	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.minecraftforge.fml.common.network.simpleimpl.SimpleNetworkWrapper.sendToAll(SimpleNetworkWrapper.java:240) [SimpleNetworkWrapper.class:?]
	at tschipp.carryon.common.item.ItemEntity.onItemUse(ItemEntity.java:116) [ItemEntity.class:?]
	at net.minecraft.item.ItemStack.onItemUse(ItemStack.java:180) [ItemStack.class:?]
	at net.minecraft.client.multiplayer.PlayerControllerMP.processRightClickBlock(PlayerControllerMP.java:489) [PlayerControllerMP.class:?]
	at net.minecraft.client.Minecraft.rightClickMouse(Minecraft.java:1606) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.processKeyBinds(Minecraft.java:2276) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.runTickKeyboard(Minecraft.java:2053) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.runTick(Minecraft.java:1841) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1119) [Minecraft.class:?]
	at net.minecraft.client.Minecraft.run(Minecraft.java:407) [Minecraft.class:?]
	at net.minecraft.client.main.Main.main(Main.java:118) [Main.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_121]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_121]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_121]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_121]
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_121]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_121]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_121]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_121]
	at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:97) [start/:?]
	at GradleStart.main(GradleStart.java:26) [start/:?]

The packet is registered correctly and has also been sent in different places, which worked fine.

Does anyone know what's going on here?

Edited October 7, 20178 yr by Tschipp