Upon booting up the technic pack, my two friends loaded into void and were disconnected shortly thereafter. Both received a message saying "Internal exception:io.netty.handler.codec.DecoderException:java.lang.NullPointerException" and were disconnected. I've checked the log all it says when that happens is that "[insert player here] lost connection." When trying to see if using the forge launcher would fix anything, the only change was the message reading "Disconnected" or "Timed Out" for the players trying to join. We all tried hosting and joining across all three machines, and the same result occurred every time. We then tried the technic pack again, but encountered the same issues. I'm including the latest.log sections, from the first joining attempt, to the failure, from both the Minecraft launcher and the technic launcher, in the case they help. Technic latest.log:

And the Minecraft one:

If there is another or better way to display the text, please let me know. I really can't figure this one out on my own, everything is as normal for multiplayer, but it just won't work. We were playing B-Team multiplayer, then decided to switch to this when we saw the update announcement, so I'm really unsure of the issue.

Thank you for reading!

Hi there!

Did you manage to get this worked out? If not, I think you might be better off getting live support from our discord server where someone can help you figure out how to get it set up, as I do not believe this is caused by a bug. Our discord if located here (if you're not already a member): https://discord.gg/WV8uRyT4

At the very least, they can help you figure out if it is a bug, and then we can go from there, but just based on the description and the logs, I'm not sure if it is a Pixelmon bug, or just an incorrect setup :)

I checked in with the discord, and was pretty much told that I should just come here and report it. Which obviously doesn't help with the issue at all. I've double and triple checked multiple mod loaders, mods, and launchers, all produce the same result: Pixelmon will seemingly have an issue and kick anyone who joins any LAN world, but any other mod combo, or even vanilla, LAN multiplayer works just fine. I even checked to see if there was something in the config that looked like it could be the issue, but I saw nothing. Whatever the issue is, it's Pixelmon specific. And it's also 9.0.0 specific, 8.4.2, and back, all work just fine. I can send any info that might be of use, it's just beyond my capabilities to figure out.

Thanks for following that up - sorry, I know it's gotta be frustrating. Thank you for your patience!

I was reluctant to try and get my husband to play along with me to test this out (mostly because I know literally nothing about servers, LAN, or hosting), but I've succeeded and had the exact same result - with my pc hosting, he was able to join, but also in the void and nothing loaded for him, and then he crashed out.

As such, this does seem to be a widespread issue, with many people now reporting issues with LAN, so I'll go ahead and forward this on to our Internal tracker! Thanks again!