WhatsApp Web does not work on Firefox - QR Code not loading

Question

When I open web.whatsapp.com in Firefox (67.0.4, Win10) the QR code is not loaded. At the same time it does work in Chrome.

What I tried:

• Reload
• Clearing the cache
• switch off add blocker
• about:config privacy.resistFingerprinting = false

What I found:

• Also a bug is described here but no solution. Unfortunately bug is closed https://bugzilla.mozilla.org/show_bug.cgi?id=1468870#c11
• In the browser console I see the following errors: Firefox kann keine Verbindung zu dem Server unter wss://web.whatsapp.com/ws aufbauen. (~Firefox could not establish a connection to server)

Answer 1

I experienced this issue after upgrading to Firefox 71 (Ubuntu 18.04 + Firefox 71), https://web.whatsapp.com stopped working, and the QR code don't load either.

Doing a Refresh Firefox worked (click on menu, Help/Troubleshooting Information, then click on Refresh Firefox...).

Also tried settings this options in about:config but it didn't work for me.

network.http.spdy.websockets = false
privacy.resistFingerprinting.autoDeclineNoUserInputCanvasPrompts = false

Answer 2

In Windows 10, going to Options under the right-hand menu, scrolling to "Cookies and Site Data", selecting "Manage Data...", then searching for "web.whatsapp.com", selecting it ("web.whatsapp.com") from the list of sites provided and then clicking on the box "remove selected" (which should have become clickable), worked for me. You will be asked to confirm that you want to erase the data and cookies and will need to restart Firefox for the QR code to load. This appears to be a less dramatic approach than refreshing Firefox.

Answer 3

Open Firefox->tap on right top setting option->preferences ->type xy ->open settings ->click manual proxy -> do not select USE THIS PROXY FOR ALL PROTOCoLs -> and left blank socks host.

Answer 4

I found a solution here: https://www.denniswilmsmann.de/2019/06/whatsapp-web-laedt-nicht-in-firefox/

• about:config -> set network.http.spdy.websockets=false
• restart firefox

Answer 5

I have been struggling with this on Firefox under W7 & W10.

Simple answer is to reload WhatsApp web from website (Ctrl+F5), NOT from cache (refresh button).

This works on "all" Windows browsers.

Thanks to the info here.

Answer 6

I've been suffering this problem for the last 3 weeks. It came out that the browser was receiving a 400 BAD REQUEST from whatsapp server because I was sending custom HTTP headers through ModHeader plugin.

ModHeader plugin is something I use to develop web applications and I usually don't disable while surfing other websites, because extra custom headers are generally ignored by web applications. Turned out that this was not the case for whatsapp. Weird.

Stop sending custom HTTP headers make the browser request be correctly handled, and the QR code appeared back,