As you can see, there's only one mod.
Created a new instance with the mod alone and it crashed.
Found the bug first on this modpack and tried to use it only alone in a clean instance.
https://www.curseforge.com/minecraft/modpacks/wynncraft-remastered

This is a known issue with GDLauncher on Minecraft versions 1.12.2 and earlier, affecting many mods. In fact, I personally fixed the bug and submitted it as a PR a while back, as you can see here: gorilla-devs/GDLauncher#1459 (comment)
This PR has not yet been merged unfortunately. There may be other work arounds I'm unfamiliar with, but this is a GDLauncher problem.