[Bug]: Opening inventory on 1.12.2 server instantly kicks you

[Mistyero]

What happened?

I joined my 1.12.2 using this client, I have the EaglerXServer plugin v1.1.0, but whenever I open my inventory or any GUI, like a chest or crafting table, it instantly kicks me from the server and the terminal has no information; from the terminal side it just looks like I closed to tab and left.

How to Reproduce

Join 1.12.2 server with EaglerXServer v1.1.0 plugin and open inventory or any GUI

Version(s)

1.1UT15 WASM-GC and 1.1UT14 WASM-GC

Agreements

• I have checked the pinned issue(s), including the one called 'READ FIRST', if this issue has been explained
• I have searched previous issues to see if this bug has already been reported
• I have ignored this and checked all the boxes
• I have given all the information I can to help the developers understand/reproduce this bug
• I have reported only one bug in this issue

[ProGamerWorking]

Did you try disabling some mods, and also what was the message it said when you got kicked out on ur screen?

[UplandJacob]

@Mistyero Can you please send a screenshot of the kick message? Also, can you send the entire server log after a server restart and you joining and getting kicked? (and if you have a proxy, send the logs for that too)

[Mistyero]

There's some variation from my previous tests, now I get kicked instantly upon logging in, and the message is just: Connection Lost End of stream Back to server list Recording 2026-07-11 153250.mp4 <https://drive.google.com/file/d/1H7RLM9OE3TPed9rOHWyVKd8urz6QBqHE/view?usp=drive_web> Then here is the entire server log: [latest.log](https://github.com/user-attachments/files/29930563/latest.log)

…

Message ID: ***@***.*** com>

[UplandJacob]

There's some variation from my previous tests, now I get kicked instantly
upon logging in, and the message is just:
Connection Lost
End of stream
Back to server list

Well you're getting this error on the server which probably isn't the client's fault:

[15:36:19] [Server thread/INFO]: Mistyero lost connection: Internal Exception: io.netty.handler.codec.EncoderException: java.lang.RuntimeException: An internal error occured.

Have you tried joining with regular Eaglercraft 1.12?

And I don't have access to that Google Drive link.

[Mistyero]

Sorry, I made the Google drive link public now. Also I'm pretty sure that message in the terminal means The client received something it couldn't handle, a plugin tried to send invalid data, or the server itself encountered a bug while creating the packet. I also think it's a client issue because I can play my server just fine with version 1.1UT13 and lower, but in 1.1UT14 or 1.1UT15 I get kicked after logging in.

[UplandJacob]

Sorry, I made the Google drive link public now. Also I'm pretty sure that message in the terminal means The client received something it couldn't handle, a plugin tried to send invalid data, or the server itself encountered a bug while creating the packet. I also think it's a client issue because I can play my server just fine with version 1.1UT13 and lower, but in 1.1UT14 or 1.1UT15 I get kicked after logging in.

Can you open your browser's Developer Tools and get the client logs for when you join the server? It's weird that it happens whenever you log in; it could have to do with handshakes.

I am thinking this might be fixed in UT16 once I release it.

[Mistyero]

Here is the log from the developer tools:
-1783806608092.log

[UplandJacob]

Here is the log from the developer tools:

Yea, it's during the handshake and because of your server setup, it seems there's some outdated connections that it's trying to send to.

I'll add some additional checks to ensure this doesn't happen in UT16.