Shopify support chat being blocked by corporate firewall?

[museumshop2]

Hi,

I've done all the steps involving my browser that Shopify recommends if support chat is not working, but am still having trouble connecting to help chat.  It says I'm in queue and wait time is 5 minutes, but it never really comes back or does anything after that.  I tried this same laptop at home and it works, so it's defintely something with my corporate network.  Shopify says "check your firewall", but what should I tell my IT helpdesk to look for exactly?  Is it an IP or port issue or something else?  I know it's a Fortinet firewall, any specific advice is appreciated so I know what to tell them exactly.