Forum der Gemeinschaft Firefox

For the last 2-3 day I have been experiencing a box that asks for my signature each time I go to a new website. I can't move the box. I can't screenshot it. Does anyone know how I can get rid of it?

All pdf files show all pages blank. It affects both those newly downloaded in Firefox and those I have stored on my PC and open with Firefox. I think this started from when the latest Firefox update was installed this week. I am up to date on Widows 11.

(AI written summary of troubleshooting steps taken before making this support thread)

Firefox version: - 152.0.1 Release - 153.0 Nightly

OS: - Windows 11 build 26200

GPU: - NVIDIA GeForce RTX 4070 SUPER

Codec package: - Microsoft HEVC Video Extensions installed from Microsoft Store

Problem

Firefox does not expose HEVC playback support, causing Twitch to disable 1440p streams encoded with HEVC.

The same machine can play the same HEVC Twitch streams in Chrome immediately after installing HEVC Video Extensions.

Expected result

Firefox should report HEVC playback support and allow playback of HEVC streams, as Chrome does on the same system.

Actual result

Firefox reports HEVC as unsupported.

about:support:

codecSupportInfo: H264 SWDEC HWDEC VP9 SWDEC HWDEC VP8 SWDEC HWDEC AV1 SWDEC HWDEC HEVC NONE

Troubleshooting already performed

- Installed Microsoft HEVC Video Extensions - Rebooted Windows - Updated NVIDIA drivers - Verified hardware acceleration is enabled - Tested with a brand new Firefox profile - Tested with Firefox Nightly - Confirmed Chrome can play the same HEVC streams

Additional observations

Chrome: - Twitch 1440p becomes available immediately after installing HEVC Video Extensions - Twitch Stats for Nerds reports:

 hev1.1.6.L150.90.0.0.0.0.0

Firefox: - Twitch reports that the browser does not support the required resolution - 1440p remains greyed out - about:support continues to report HEVC NONE

Reproducible tests

Firefox console:

MediaSource.isTypeSupported('video/mp4; codecs="hev1.1.6.L150.90"')

Result: false

MediaSource.isTypeSupported('video/mp4; codecs="hvc1.1.6.L150.90"')

Result: false

navigator.mediaCapabilities.decodingInfo({

 type: "media-source",
 video: {
   contentType: 'video/mp4; codecs="hev1.1.6.L150.90"',
   width: 2560,
   height: 1440,
   bitrate: 8000000,
   framerate: 60
 }

})

Result: {

 supported: false,
 smooth: false,
 powerEfficient: false

}

For comparison:

MediaSource.isTypeSupported('video/mp4; codecs="av01.0.08M.08"')

Result: true

navigator.mediaCapabilities.decodingInfo({

 type: "file",
 video: {
   contentType: 'video/mp4; codecs="av01.0.08M.08"',
   width: 2560,
   height: 1440,
   bitrate: 8000000,
   framerate: 60
 }

})

Result: {

 supported: true,
 smooth: true,
 powerEfficient: true

}

Additional note

Setting:

dom.media.webcodecs.h265.enabled = true

causes HTML5 codec test (https://html5test.co/) to report H.265 support, but does not change:

- about:support - MediaSource.isTypeSupported() - MediaCapabilities.decodingInfo() - Twitch HEVC playback availability

Question

Is this a known issue with HEVC Media Source Extensions support on Windows 11 build 26200, or is there another requirement for Firefox to expose HEVC playback capability through MediaSource and MediaCapabilities when the Windows HEVC codec is installed and functioning in Chromium-based browsers?

Hi, I am on Firefox version 150, but I can't see the new free VPN button. I wanted to try it out, but I can't see it anywhere in my settings. Any advice would be appreciated.

I was following https://support.mozilla.org/en-US/kb/built-in-vpn?utm_source=www.firefox.com&utm_medium=referral&utm_campaign=whatsnew-150#w_turn-on-vpn-in-firefox , but there isn't a button like it shows

About two months ago, after various Windows and Firefox updates, I can no longer make Firefox the default browser. In Windows Default Apps the only option for FF is to make it the default program for Adobe Acrobat Document. Choosing Make FF Default through the browser does not work either. Additionally, I’ tried numerous suggestions, using AI help offered by both FF and Chrome, without success.

The OS is not allowing me to make Firefox the default browser. Is there any way around this?

Any suggestions?

Firefox: 155.0.1 (64-bit) Windows 11 Pro Version: 25H2 OS build: 26200.9278

Thanks

I just turned on Firefox's free VPN, but I didn't see a way to choose a particular server. I'd like to watch some videos from other countries, but those providers won't let me watch them unless they think I'm in their country. I can do this with other VPNs because I can choose a server that is in that country. Why can't I do that in Firefox? Or can I?

Google has added some AI 'ads' to their title page? This just appeared a day or so ago on my system. How did I remove it, block it? Attached is an image of what I am asking about. What is interesting is in Chrome I can explicitly turn this junk off. But when using the Google search title page with Firefox, there appears to absolutely no way to disable it... very nasty way of forcing you to use Chrome?

Moderator note: Edited per OP's request.

This is only an issue in Firefox, so it's not an issue with my ISP or anything. Chrome shows my location correctly. Around 2 weeks ago after an update to firefox, it's just been constantly showing my location as Dublin. I'm in the UK. Certain sites show it correctly, some don't. Google doesn't show it right.

Several sites i check show it in the UK correctly, but google and a couple others show as in Dublin. I only run a limited number of extensions, Ublock surfshark, and bitwarden. If I put a uk location on surfshark, then google is right, but turning it off and then it is back to ireland.

I am running Firefox version 153.0.1 on a 64bit install of Windows 11.

A few days ago I had to factory reset my computer, including a clean Windows install. Since then, when attempting to access https://vodafone.cz/muj/prihlaseni, I get an Imperva Error 15 "Access Denied" error screen - screenshot attached here. Clicking the Imperva logo on the bottom of the error message leads to https://www.imperva.com/why-am-i-seeing-this-page/?src=23.

I was able to access the site in the past, most recently on July 8, 2026 - this would have been Firefox version 152.0.5.

This error persists in troubleshooting mode but not in private/anonymous (with or without extensions enabled), nor does it appear in Microsoft Edge or Firefox on Adroid.

Clearing cookies and cache did not help - in fact the error first showed up on a clean install of Firefox, when there weren't any cookies or cache stored yet. I've tried different DNS over HTTPS settings and listing the site as an exception in settings, but none of this made a difference. Enabling Firefox's built in VPN also made no difference, regardless of the selected location.

I found a recent post (https://support.mozilla.org/en-US/questions/1588627) describing a similar issue on a different website and tried the suggestion listed there to try a fresh profile - this seemed to work, but within a couple of minutes of browsing the error message returned. I've even reinstalled Firefox entirely, but this too did not help for long.

Interestingly enough, the error message lists a proxy IP address (not blacked out on the screenshot) despite the fact that I am not using a proxy.

The website provider's tech support claims this is an issue on the user side, not theirs - they have not been able to replicate the issue.

Is there anything I'm missing that would explain why this is happening?

Thanks!

I was not given a VPN setup on restarting Firefox, and have no VPN icon in my toolbar. I have tried using customise toolbar, but there is no VPN icon to add back. Version 150.0, automatically opened to "What's New in Firefox 150" on starting Firefox, just without a new VPN icon. Thanks

I live in Europe, where this stupid age verification law is in effect. I get around this by using a VPN. The problem is that I have two Firefox profiles set up with the same VPN and the same country. The issue occurs on X (formerly Twitter). On one profile, the VPN works as it should and I no longer need to verify my age, but on the other profile, the VPN has no effect and X (Twitter) asks me to verify my age. Yet the VPN is definitely enabled. I’ve cleared the cache and cookies, but nothing helps. It’s driving me crazy. Does anyone have any idea what the problem might be?

after using firefox for many, many years, today i keep getting a request for a primary password. i have never had to have this before & do not know why is being asked now...when did this become a requirement & how do i get my password information back? i have never set up any kind of password for firefox. i have tried current passwords & old passwords i would have used & it will not accept anything.

I can open gmail but it does not refresh. If I clear the cache it refreshes the first time only. Sometimes I get a message saying that my account is temporarily unavailable but I can access gmail with no problem on my iPhone, android tablet and with Google Chrome without any problems. Turning off the Advanced Tracking does not resolve the problem.

I had opened a support ticket #447010 with Mozella support and they told me that they can not help me, and sent me here. I am "dead in the water" so to speak. It appears that since Firefox downloaded update 153.0(20260715202819) I have had many issues that appear to be getting worse by the day, and now I cannot open or run my email app. I have not wrote down all the errors (sorry) but here are a couple: 431 Request Header Fields too large, the application is having trouble connecting to the server, unable to load the email from Mozella support. After the update (153.0) my bookmarks have moved to somewhere, the sign on for my email app has changed ( use to click on the firefox icon on the bottom tool bar and the sign in box for optonline.net would be there. I understand that sometimes updates (new and improved) make changes to what users have use to for years. Now is have a browser that is not functional and needs to be corrected, I trust you can help and get this sysem usable again, because right now it is not usable. I presume if and when you respond to me issues it will be at this location and not an email. Please help. Thank you