I'm trying to access whatsapp web (https://web.whatsapp.com/) thru my company's proxy. It won't load the QR code, and on the console I find these messages Firefox can’t establish a connection to the server at wss://web.whatsapp.com/ws. .... (app.f2d64e26d366144085e4.js:2:1197101) All other sites do work thru the proxy, and I've tried switching modes (e.g. use system proxy, use manual settings, use proxy.pac, ...) to no avail. Whatsapp web is working on the same machine when I'm home (no proxy), and via EDGE (both via proxy, and direct). I searched for some similar bugs (wss via proxy), but those were apparently fixed in FF 57 or so. Thanks!