Strange Network Issue

I'm not sure if anyone can explain this issue. I'm about to setup a server to run a domjudge programming competition (I've done this successfully a few times before). I installed a fresh linux install yesterday and loaded up the domjudge website to read through the directions (everything was fine).

Today, for no reason that I can comprehend, I am now unable to load the domjudge website on my school's network. I checked on my cellular network, and everything is fine. I checked with my IT staff, and they say they are not blocking traffic to the domjudge website. For some reason, all our traffic that we send there is not being replied to.

Does anyone have a theory for why this is happening?

Thanks, Matt Fahrenbacher Niles West High School