A problem occurred configuring root project 'extremes-1.19.4'.

Could not resolve all files for configuration ':modImplementation'.
Could not find com.eliotlash.mclib:mclib:20.
Searched in the following locations:
- file:/E:/extremes-1.19.4/.gradle/loom-cache/remapped_mods/com/eliotlash/mclib/mclib/20/mclib-20.pom
- file:/C:/Users/3/.gradle/caches/fabric-loom/minecraftMaven/com/eliotlash/mclib/mclib/20/mclib-20.pom
- file:/E:/extremes-1.19.4/.gradle/loom-cache/minecraftMaven/com/eliotlash/mclib/mclib/20/mclib-20.pom
- https://maven.fabricmc.net/com/eliotlash/mclib/mclib/20/mclib-20.pom
- https://libraries.minecraft.net/com/eliotlash/mclib/mclib/20/mclib-20.pom
- https://libraries.minecraft.net/com/eliotlash/mclib/mclib/20/mclib-20.jar
- https://repo.maven.apache.org/maven2/com/eliotlash/mclib/mclib/20/mclib-20.jar
- https://repo.maven.apache.org/maven2/com/eliotlash/mclib/mclib/20/mclib-20.pom
Required by:
project : > software.bernie.geckolib:geckolib-fabric-1.19.4:4.2
Could not find com.eliotlash.mclib:mclib:20.
Searched in the following locations:
- file:/E:/extremes-1.19.4/.gradle/loom-cache/remapped_mods/com/eliotlash/mclib/mclib/20/mclib-20.pom
- file:/C:/Users/3/.gradle/caches/fabric-loom/minecraftMaven/com/eliotlash/mclib/mclib/20/mclib-20.pom
- file:/E:/extremes-1.19.4/.gradle/loom-cache/minecraftMaven/com/eliotlash/mclib/mclib/20/mclib-20.pom
- https://maven.fabricmc.net/com/eliotlash/mclib/mclib/20/mclib-20.pom
- https://libraries.minecraft.net/com/eliotlash/mclib/mclib/20/mclib-20.pom
- https://libraries.minecraft.net/com/eliotlash/mclib/mclib/20/mclib-20.jar
- https://repo.maven.apache.org/maven2/com/eliotlash/mclib/mclib/20/mclib-20.jar
- https://repo.maven.apache.org/maven2/com/eliotlash/mclib/mclib/20/mclib-20.pom
Required by:
project : > software.bernie.geckolib:geckolib-fabric-1.19.4:4.2 > software.bernie.geckolib:geckolib-core:2.0.4.1

i just wanted to add geckolib to my project, but i cant

The GeckoLib maven seems to be missing entirely from the list of allowed locations. Double check that you have followed the Installation page properly.

I'd recommend you join the discord server, as Github is not the best place for support.