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I am a Cacti developer and we are considering switching from FontAwesome Web Fonts to Tabler Web Fonts. However, on Firefox for Windows only, we are having a major slowdown when using the Tabler SVG based webfonts. The page load is first stalled by Firefox apparently loading all the Web Fonts, which would appear normal with any browser (though exceedingly slow on Firefox for some reason).

However, once the page is loaded, when going off tab to another browser tab, and then back to the Firefox tab that includes the Tabler webfonts, there is a 3 second delay before the tab switches. When we enable the performance analyzer, we find that the delay is almost 100% Reflow of the page, even though the page is static as this point (no changes) from the last time it was activated.

We do not have this issue on Firefox for Linux, MS Edge or any other Chromium browser, only Firefox on Windows. I'm using the latest version 134. Should I be opening a bug?

Firefox is no longer compatible with my bank's system. I can't log in with the secure access code the bank sends to verify my identity when using Firefox. The bank says it is a problem with Firefox. Other browsers work flawlessly ... are you working on a solution? I only use Firefox unless forced to use something else ...

I don't know from which version of FF it started exactly, but recently loading of websites starts after huge pause or fails at all, the same is with elements of web pages if those are located on different domain. This is only FF problem, other browsers load pages instantly. I have tried to delete cache, data and FF completely and reinstall anew, it doesn't help. I can only guess what causes it, probably some DNS connection issues.

Suddenly this morning Firefox stopped connecting to any websites. It never gives an error message, it just tries to connect forever. Chrome and Edge can both access the internet without problems. I'm running Windows 11 Pro, and here's what I've tried so far:

Malwarebytes disabled Firewall disabled Turned off all add-ons/extensions Firefox uninstalled and reinstalled Firefox, Windows, Malwarebytes, etc all updated Cache & cookies cleared Refresh Proxy use disabled IPv6 enabled DNS prefetching set to "true" Full malware scan by Malwarebytes Computer restarted (several times)

Any other ideas? Thanks!

Home Internet speed via cable 500 Mbps. When checking the Internet speed through the Firefox browser (version 133.0.3), incoming and outgoing about 250 Mbps. That is, the browser cuts the speed twice. When checking the speed through Google Chrome (version 145.0.7632.160), the Internet speed is about the declared 500 Mbps. Please help solve the problem with Internet speed through the Firefox browser.

I'm using Mac OS 11.7.10. Firefox desktop no longer allows me to browse the internet. It just keeps spinning wheels. I've downloaded the newest version and it still crashes. What can I do?

I can use edge and my speed tests perfect on speed test. If I use Firefox the upstream is half. I only have block installed but doesn't matter if I disable or not.

After a recent update to Firefox 133.0.3 (on Ubuntu GNU/Linux 22.04), Firefox is having difficulty connecting to websites and exhibiting some other odd behavior:

- After initially starting Firefox, it will load websites (e.g., previously open tabs) for up to 30 seconds. After that, it will not load any website in a new tab, showing the loading animation for several seconds before stopping all activity and just displaying an hourglass icon in the tab. These sites can be connected to in other web browsers. - After closing Firefox, its process is still running; I have to manually find its pid and kill it. - If I start Firefox from the terminal, I see these messages when it starts having trouble loading websites:

libva info: VA-API version 1.20.0 libva info: Trying to open /snap/firefox/5437/gnome-platform/usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so libva info: Found init function __vaDriverInit_1_20 libva info: va_openDriver() returns 0

So basically, I'm trying to add a 2FA code, homever when I scanned the code using google authenticator, everything went normal. Homever, when I try to put in the code, firefox only lets me put 5 digits but not 6. Any solutions?

I’ve been troubleshooting a strange networking issue in Firefox that I haven’t been able to pin down, and it seems to be specific to Firefox’s network stack rather than my system or connection.

On several high-traffic sites that sit behind Cloudflare (Discord, Shopify storefronts, some SaaS dashboards), Firefox occasionally stalls during page load. The request shows up in the Network panel as pending for several seconds before finally completing. Sometimes the page partially renders and then hangs until the stalled requests finish.

A few things that make this confusing:

• The same sites load instantly in Chromium-based browsers on the same machine and network • The issue persists even in Firefox Troubleshoot Mode with extensions disabled • DNS over HTTPS on/off does not appear to change behavior • Packet captures show the TCP connection is established quickly, but some HTTP/2 streams appear to wait before data begins flowing • If I force HTTP/1.1 using a proxy for testing, the issue disappears

System details:

OS: Windows 11 Firefox: latest stable release Connection: fiber, low latency, no packet loss locally No system proxy configured

Things I’ve already tried:

• Clearing cache and site data • New Firefox profile • Disabling hardware acceleration • Testing with network.http.http2.enabled toggled • Comparing HAR logs with Chromium

One thing I noticed in the Firefox networking logs is that multiplexed streams sometimes wait behind earlier streams longer than expected, almost like there’s some internal prioritization or queue behavior happening. I’m wondering whether this could be related to HTTP/2 prioritization logic, connection coalescing, or how Firefox handles Cloudflare edge endpoints.

Has anyone seen similar behavior or knows whether there are any advanced networking prefs in about:config worth experimenting with (connection limits, HTTP/2 concurrency, etc.)?

Curious if this might be a known quirk with certain CDNs or just something unique to my environment.

Hi Firefox Team,

I wanted to ask, whether you know any solution to my streaming problem. I noticed that my download speed is incredibly fast, when I am running a download in the background of my PC. This can be a windows-update or updating a game via steam. But when I am not downloading anything, then Youtube cant even stream 360p without buffering every 10 seconds. I feel like the Firefox-Browser is not telling my PC that it needs the internet and thus does not get it, but when another program needs internet, It gets enough to work.

Working on setting up a new PC build. I've had to use some PC support website chats and many of them have just not acted right? For example, one would allow me to start a chat but then sent me directly to closing the chat like we were finished. The others would lock up my Firefox many times. Anything come to mind as to why this is happening? Windows 11 Pro v24H2 and latest Firefox version.

On Mac but not on Safari Firefox buffers for minutes before connecting. I’ve tried clearing the cache with no improvement. Until recently I never had this problem and as I said there’s no problem on Safari.