How to setup FiveReborn in a local network? Getting Error (7)

I’m in my college that uses a proxy server. I want to host a server so that my friends can access it in the same LAN that I create using my mobile phone’s hotspot. I dont want to use the internet and Kanersps did tell me once before that Internet isnt necessary to use FiveReborn.
I used FiveReborn before for hosting a server online.

Please tell me how to setup the server for offline LAN use. Also, if I try to open FiveReborn Client, just open, I get a “Error (7) Bootstrap check failed sort-of thing, check updater.fivereborn.com”. Please help me out.