Next time, remember to refresh, or leave and come back to the website when you get errors like this. If it doesnt work come back later, minehut might be working on website updates, and may of closed the website while they update the web
This is a mod not a plugin. It needs fabric (I think) so it wont get added to minehut. For now just go on fabric with all your friends and use the mod.
I can relate. I spent nearly 2 months on 2 servers that just wont get out of hibernation...
I recommend contacting minehut staff, as they have helped people with similar problems in the past.