Hello Aternos Staff!
I have noticed that when installing Advanced Rocketry on my server, it required a library which does not have the 1.12.2 update on it.
Even though by looking on curse, there is 1.12.2 files on to the side of the description page.
Click here to see location of downloads
https://www.curseforge.com/minecraft/mc-mods/libvulpes
A Small library containing helpers for multiblocks, recipe handling, power handling, and some other small features.
Please do note, this mod is a requirement for the 1.12.2 versions of Advanced Rocketry!
Thanks for reading, and I hope you accept this!