19 votes

If you're having trouble with Firefox, try disabling HTTP3 in about:config

@Johannes Baiter 👶 💻:
If you're having trouble with #firefox, try disabling HTTP3 in about:config with the 'network.http.http3.enabled' key. After setting this and restarting Firefox everything worked again.

7 comments

  1. [5]
    feigneddork
    (edited )
    Link
    So I woke up this morning and Firefox suddenly stopped loading all of its tabs on my M1 Mac Mini. My first thought was my router suddenly crapped out or my modem was giving me issues. I restarted...

    So I woke up this morning and Firefox suddenly stopped loading all of its tabs on my M1 Mac Mini. My first thought was my router suddenly crapped out or my modem was giving me issues. I restarted the router and I got absolutely nothing - couldn't even go to the URL.

    I tried my Macbook Pro and that seemed to be fine so I restarted my machine. About ~5 mins later the same problem in Firefox. I tried a new website in Edge, and that worked fine. Essentially, Firefox was the culprit.

    This tweet helped me fix it. If you can't see it, here's the content:

    If you're having trouble with #firefox, try disabling HTTP3 in about:config with the 'network.http.http3.enabled' key. After setting this and restarting Firefox everything worked again.

    Bear in mind that for me, I had to run ps aux | grep firefox on the Terminal to find a lingering Firefox process, run a kill <pid> to end it, and then restart Firefox for the change to be properly applied.

    I hope this helps anyone else in a similar place.

    EDIT: A bugzilla thread for those who are interested in seeing this get solved (the above really isn't a permanent fix, but a temporary bodge) https://bugzilla.mozilla.org/show_bug.cgi?id=1749908

    8 votes
    1. 3_3_2_LA
      Link Parent
      Ohhhh, now I get it, I was helping debug this on my mom's M1 macbook haha. Glad to know it wasn't just me

      Ohhhh, now I get it, I was helping debug this on my mom's M1 macbook haha. Glad to know it wasn't just me

      3 votes
    2. parsley
      Link Parent
      Thanks! I was going crazy over this. I have closed like a year worth of leftover tabs and almost reset my profile trying to fix this.

      Thanks! I was going crazy over this. I have closed like a year worth of leftover tabs and almost reset my profile trying to fix this.

      2 votes
    3. [2]
      Protected
      Link Parent
      I'd be curious to know if just disabling telemetry would also have fixed the problem.

      I'd be curious to know if just disabling telemetry would also have fixed the problem.

      2 votes
      1. parsley
        Link Parent
        They mentioned somewhere that there are other services. Of the top of my head the captive portal functionality or autocheck for updates require external services. Certificate revocation uses a...

        They mentioned somewhere that there are other services. Of the top of my head the captive portal functionality or autocheck for updates require external services. Certificate revocation uses a special service separated from the auto updater too.

        1 vote
  2. inwardpath
    Link
    This actually ended up being a solution for a different problem for me. For quite a while now I've had issues where Firefox (on Win 10 / 11) would just seemingly at random not load images and...

    This actually ended up being a solution for a different problem for me. For quite a while now I've had issues where Firefox (on Win 10 / 11) would just seemingly at random not load images and various resources from a particular group of sites, until I cleared the cache.

    Disabling HTTP3 fixed the issue completely. The suggestions involve modifying some HTTP3 settings but it seems disabling HTTP3 instead fixes it vs. prolonging the time between problems. (https://bugzilla.mozilla.org/show_bug.cgi?id=1735595)

    It may also be placebo, but video loading and site "snappiness" in general on many sites seems better after this adjustment. Seems FF's HTTP3 implementation was not ready for primetime

    4 votes