I started a Minecraft server with Forge today using an existing world. Got it up and running, and I could join my own server from the same computer. It played fine. However, when my brother joined from another computer, all the terrain didn't load and he got stuck floating in midair. The console showed these errors:
This is the log from the server root folder: https://pastebin.com/BdYDWUcu
And this is the debug log from the same folder:
I've tried to reinstall Forge and Optifine on both mine and my brother's computer (didn't work), used the backup dat file of the world (which worked once, he then got disconnected almost a minute in, then the problem repeated itself when he connected the following times), created a new world (didn't work).
The only difference between us is that I'm using a shader pack and he's not. We played together with no problem using this same world, same setup on an Aternos server.
Please help. Thank you.