My 1.12.2 forge server crashes on startup with only betterhud-1.12.2-1.4.1 in mods folder.
Here is the crash report:
crash-2019-09-05_20.21.26-server.txt

The problem is that classes of the package "net.minecraft.client" are repeatedly accessed even though they are not loaded when the server is started.

This mod is in desperate need of a SidedProxy. I will start working on it soon.