"Disconnected" error message, "Can't serialize unregistered packet.'" in the server logs.

[Chimel]

Hi

I've been trying to fix this for 2 hours, i can't connect to a server and I have no idea why, version is good, I'm using the .jar launcher and not the twitch one, MultiMC does the same. 

When I try to connect it either tells me "Disconnected" (80% of the time) or "Internal Exception: java.io.IOException: An existing connection was forcibly closed by the remote host", I tried disabling my firewall and anti virus, I unplugged my ethernet cable and made a Connection Sharing between my computer and my phone with my mobile data, but the same still happens.  

It's driving me crazy, please help.

The website doesn't allow me to upload my logs for some reason so I put them in a google drive https://drive.google.com/file/d/15yXarIxTVEwEnTwozFszb5mCoFx_BEg_/view?usp=sharing  

The pack is Project Ozone 3, the server works fine for everyone else