Try messaging him on the forums, if you cannot do that then through discord is the best way. If you cannot do either than can you explain why please? What error shows up or what problem you are having?
Minecraft PC IP: play.cubecraft.net
CubeCraft Games
AnimalTamer1
AnimalTamer1
You can still message him and wait for him to respond at any given point when he is online and has time. (: