Server closes after starting up

[Bengon]

 Alright so I started making my own modpack for use with MultiMC to play with some friends and the completed modpack works fine when I start it up. The server however doesn't and gives me an error after loading some files and stops working before needing to be closed.

 

I checked log and see this: 

Caused by: java.lang.ClassNotFoundException: net.minecraft.client.renderer.block.statemap.IStateMapper
	at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)

 

I've attached the entire log, but I'm not sure what this means. Anyways I have few theories on what's going on, but I'm not an expert, and this is my first modpack so I'm not sure if they're correct so some advice would be helpful.

 

So what I'm thinking is:

1.I have a client mod in the server mod folder causing it to crash (I've removed all the ones I know)

2. There is something wrong with my installation of forge or maybe version

3. One of my mods are conflicting with each other (I'm not sure about this because the modpack only has issues with the server)

crash-2020-05-20_03.12.27-server.txt