I'm trying to start a modded forge server to play with friends, installed the server client, did everything with the minecraft .jar file to create the server files, created a mods folder and placed the mod in it. The mods work and run just fine in singleplayer but do not work within the server. The server runs perfectly but only client-side mods work.

This is a custom mod pack that has been tested and works just fine in single player. I did try the server WITHOUT client side mods (or least removed the known client mods).

Here is the download code. a0TWt630

Minecraft Version: 1.20.1

Forge Version: 47.4.10

openjdk version: 21.0.9

How are you starting the server? If it's a .bat file, show the contents.

Also, please post server logs to a site such as https://mclo.gs and post the link here.

2 hours ago, Ugdhar said:

How are you starting the server? If it's a .bat file, show the contents.

Also, please post server logs to a site such as https://mclo.gs and post the link here.

I am using the "server.jar" file. I do also have a "run.bat" file too.

I think I did this right? https://mclo.gs/qN5gIYf

You need to use the run.bat file for 1.20.1. The server.jar file launches the vanilla Minecraft server. The log you've sent shows a vanilla server running, not a Forge server running.

I just ran the run.bat file now it gives an error and won't load. Not sure how to send the cmd here tho. But it runs a bunch of commands and stops saying "press any key" and closes if I press anything.

12 minutes ago, Jonathing said:

You need to use the run.bat file for 1.20.1. The server.jar file launches the vanilla Minecraft server. The log you've sent shows a vanilla server running, not a Forge server running.

See if the the log has changed since you did the run.bat, and if so upload that one to the logs site and share the link.

Don't use the server.jar, that just runs the vanilla server.

8 minutes ago, Ugdhar said:

See if the the log has changed since you did the run.bat, and if so upload that one to the logs site and share the link.

Don't use the server.jar, that just runs the vanilla server.

Here is the latest log.
https://mclo.gs/pYkBPJA

I'm unsure which ones, but you have mods that are trying to load client-only classes (like things related to gui screens, mouse input), and the client does not exist on the server.

You will need to identify and remove those mods from the server.

20 minutes ago, Ugdhar said:

I'm unsure which ones, but you have mods that are trying to load client-only classes (like things related to gui screens, mouse input), and the client does not exist on the server.

You will need to identify and remove those mods from the server.

I take it there is no easy way to find these client only mods? Also is that the only issue so far?

Just removed more client mods. Not sure if its all mods but still crashes. Here is a newer report. https://mclo.gs/CsIWgR2

Remove bettercombat

13 hours ago, TileEntity said:

Remove bettercombat

Is that causing an error?

This is in that log

	[26Jan2026 20:59:00.322] [main/FATAL] [net.minecraftforge.fml.ModLoader/CORE]: Error during pre-loading phase
	net.minecraftforge.fml.ModLoadingException: Mod §ebettercombat§r requires §6playeranimator§r §o1 or above§r
	§7Currently, §6playeranimator§r§7 is §o§nnot installed

Sorry for the formatting, it did it on me automatically. I'd be willing to wager that the playeranimator mod won't run on a server, as there are no animations on a server, that's a client thing.

1 hour ago, Ugdhar said:

This is in that log

	[26Jan2026 20:59:00.322] [main/FATAL] [net.minecraftforge.fml.ModLoader/CORE]: Error during pre-loading phase
	net.minecraftforge.fml.ModLoadingException: Mod §ebettercombat§r requires §6playeranimator§r §o1 or above§r
	§7Currently, §6playeranimator§r§7 is §o§nnot installed

Sorry for the formatting, it did it on me automatically. I'd be willing to wager that the playeranimator mod won't run on a server, as there are no animations on a server, that's a client thing.

Ok. Right now I am trying to load mods to see what works and what does not. Seems some mods are causing it to crash but I do have a handful working now.