Steps to Reproduce

1. Install these mods onto an forge 1.12.2 aternos server:

OptiFine
Just Enough Items
JourneyMap
HT's TreeChop
Mrcrayfish's Furniture Mod
Quark
AutoRegLib
Carry On
AppleSkin
CreativeCore
ReachFix
OreLib
Dynamic Surroundings
The One Probe
Epic Knights
Immersive Combat
Material Changer
Mo' Bends
GraveStone Mod
Neat
Mouse Tweaks
Serene Seasons
AmbientSounds 6
Spartan Weaponry
Spartan Shields
Traveler's Backpack
Somnia Awoken
Tough As Nails

2. Try to start server.

3. The server fails to start.

Expected Behavior

The server starts without problem

Actual Behavior

The server crashed

Your Minecraft version

Forge 1.12.2

Your error log

https://mclo.gs/mRtPpGK

Additional Comments

When removing the Epic Knights mod, the server starts normally. All of these mods work without issue on singleplayer, too. I have no idea what is causing it. On further inspection I did found this however:

Examining file [1.12.2]-Epic-Knights-Armor-and-Weapons-6.2v(uncomplete).jar for potential mods
Located mcmod.info file in file [1.12.2]-Epic-Knights-Armor-and-Weapons-6.2v(uncomplete).jar
The mcmod.info file in [1.12.2]-Epic-Knights-Armor-and-Weapons-6.2v(uncomplete).jar cannot be parsed as valid JSON. It will be ignored.
 
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Conclusion

• I agree that I am inattentively reading the description, just filling out everything

I found a fix, however this is not very optimal- Installing an earlier version, 4.13 instead of the newest, 6.2 fixed this issue. Hopefully the devs will fix it 😢

You can try to use this file.
I fix it by myself and delete some item like netherite weapons and crossbow
But I can't test much so it maybe still has bug

https://drive.google.com/file/d/15q6sHI0cd4uaLro473Ltobl_X59rHofx/view?usp=sharing