This one is quite simple. Cloudflare blocks http://repo.spongepowered.org/maven and only accepts from https://repo.spongepowered.org/maven

solution: change the build.gradle

(You should NEVER use http imo)

so this seems to be solved

Those URLs are outdated otherwise anyway due to some Sponge infrastructure changes. I'll update it for all the mods when I start making new 1.12.2 builds again. (I think it's already updated for malilib atm.)