seams to when put in mods servers folder not load fine, LAN server.

1. What version of the library are you using?
2. Does the version match what the mod requires?
3. And if yes, please describe further.

Also could you please post a Pastebin of the full error log.

I ran the file on a server myself and got an error log https://pastebin.com/yX6tAyMW

Line 76 is

public static final EntityModelLayer fabric_shield_model_layer = new EntityModelLayer(new Identifier(MOD_ID, "fabric_shield"),"main");

Probably another dev environment check would be good to have. We could split the making and the assigning of the variable so that it is assigned inside of the onInitialize dev check

Problems i see:

"Contributors" tag in fabric.mod.json

[16:24:58] [main/WARN]: @mixin target net.minecraft.class_756 was not found fabricshieldlib.mixins.json:RendererMixin

Line 76 in FabricShieldLib

I have a commit that should fix this issue

it's because the RendererMixin should be under "client" in fabricshieldlib.mixins.json it's trying to inject into rendering code that doesn't exist on the server.

but there also might be more stuff running on the serverside that is clientside only

Im going to commit a change in a second that should fix the model_layer problem.

Sorry, I added commit that moves the modelLayer, and renderBanner to the Client in a new commit

Fixed in 1.4.2