Postman Web being blocked on school network

First time using Postman. Trying to utilize the web version of Postman but having issues on a school network. Our filtering service is not blocking it, but when I try to load web.postman.co/build, I only receive the HTML table borders only and no content. I think it could be a firewall/port issue? Is there specific port that should be unblocked or utilized for Postman Web?