Business Firewall Blocking Access to an Online Web Tool

I am testing a web based tool from a business network and noticed that the site does not load when connected through the office firewall, although it works normally on a separate connection. The same issue can occur with browser based services such as Ind***.m***, so I am trying to understand whether the firewall is blocking a domain, HTTPS request, DNS resolution, or a specific category of web traffic. Has anyone dealt with a similar situation on a NETGEAR business firewall, and what is the safest way to identify the rule responsible without unnecessarily weakening the firewall policy