Firefox Community Forum

A recent set of system updates appears to have made most website videos not play in Firefox.

When I inspect the Developer Tools - > Console tab the most detail Firefox gives are an error line similar to: Media resource URL could not be decoded, error: Error Code: NS_ERROR_DOM_MEDIA_METADATA_ERR (0x806e0006)

Internet searches for the error name and error hex do not appear yield any applicable troubleshooting, nor any methods of collecting additional problem data.

How can I obtain more detail on where the error is happening and how Firefox might be interacting with other packages present on my system?

Arch Linux has some older ffmpeg-compat packages, but those don't appear to match any of the web results, in that they're even older versions of ffmpeg.

yay -Ss ffmpeg-compat aur/ffmpeg-compat-55 2.3.6-4 (+24 0.00)

   Compatibility package for ffmpeg to provide versions 55 of libavcodec, libavdevice and libavformat, not anymore provided by the ffmpeg package

aur/ffmpeg-compat-54 1.2.12-4 (+87 0.00)

   Compatibility package for ffmpeg to provide versions 54 of libavcodec, libavdevice and libavformat, not anymore provided by the ffmpeg package

I recently switched ISP and now when I try to google anything with firefox I keep getting this message appear:

"Our systems have detected unusual traffic from your computer network. This page checks to see if it's really you sending the requests, and not a robot."

It prompts me to click 'I am not a robot' then pick out which lights have cars etc in them. Worked fine before the ISP change. Some notes:

- This does not occur on Microsoft Edge or Chrome. - The only add on I have is Ublock but it still does this when I have that disabled. Plus I have Ublock on Edge and there are no issues.

If it's my IP address, then why does this ONLY appear when I use Firefox? Surely it would also appear when using google on any browser if my IP address was in question...

From what I am reading online, my only option is to either: - Use a different search engine ; or - Use a different browser.

I'm curious to hear other people's thoughts on this.

Majority of the songs do not play and I'm given with a pop-up, "Spotify can't play this right now. If you have the file on your computer you can import it."

I will play a song from a playlist and is given that pop-up, it will continue skipping to the next song until it plays, but only for 9-10 seconds until the song mutes, to specify, the dot (when hovered on the progress bar) will still move, indicating that "it's playing".

Some clarifications: 1. I use Spotify Desktop app (windows), Spotify App (android), and Spotify Webplayer on Chrome and Firefox. Everything works just as fine on all of these, except for Spotify Webplayer on Firefox. 2. Skipping to a later timestamp does not unmute the song. 2. I have Spotify Premium 3. I have no VPN 4. I am running Firefox with an ad blocker 5. I am running Chrome with an ad blocker (same ad blocker in Fifefox) 6. I am running Firefox to the latest version (Firefox 119.0.1 (20231106151204))

What I've done so far: 1. Cleared caches and data. 2. Updated my Windows to the latest update available - Win10 v.22H2 3. Signed-out of Spotify for all my devices, then logging-in first on Spotify Desktop (this automatically redirects to Firefox webplayer) 4. Ran Firefox on "Troubleshoot Mode" 5. Un-checked and re-checked "Play DRM content" setting. 6. Disabled and re-enabled the plug-in "Widevine Content Decryption Module by Google Inc". (this plug-in is last udpated on November 17, 4.10.2710.0

I'm including this link from Spotify's Community page.. where two other users, who commented it is only with Firefox (webplayer), are experiencing the same problem as I am. https://community.spotify.com/t5/Desktop-Windows/Spotify-can-t-play-this-right-now-If-you-have-the-file-on-your/m-p/5679914#M123192

I've just switched to firefox from brave, and theres no button on twitch to enable picture in picture. Using the keyboard shortcut (cmd+option+shift+]) works, but I'd much rather click something on the screen. On brave there used to be a picture in picture button alongside settings, theatre mode, and fullscreen buttons, but on firefox this has been replaced by a clip button. There's no option for it if I right click (this works on youtube), and no option in the address bar for either twitch or youtube. I've tried disabling all my extensions and lowering protections but nothing seems to work.

Important update! On March 14, 2025, a critical root certificate in Firefox will expire. If you’re still using an older version (before Firefox 128 or ESR 115.13+), it’s crucial to update to Firefox 128 or newer to avoid issues with add-ons, DRM-protected content, and other features.

For full details, check out Update Firefox to prevent add-ons issues from root certificate expiration.

If you have questions about the update or need help with the process, this is the place to ask! Whether you’re just starting or you’ve already updated and want to share your experience, we’d love to hear from you.

Let’s come together, share tips, and ensure we’re all prepared. Drop your questions or insights below!

When I'm in full screen mode, The Apple, "Firefox" "File" "Edit" "View" "History" "Bookmarks" "Tools" etc menu bar shows up at the top and won't disappear. On my iMac Pro, it doesn't show up. i.e. Off.

I can't figure out what is the setting to make sure it does not appear. I went digging everywhere and can't figure it out. If you could tell me what config, etc I'm missing I'd appreciate it.

Screen shot attached to show which menu bar I mean.

My firefox is up to date: 126.0 (64-bit)

I view a lot of pdf documents via firefox, the light gray background makes my eyes and head hurt after prolonged usage. In the past I found a solution on this forum that advised to set pdfjs.viewerCssTheme to "2" in about:config. This set the background of pdf viewer to black/dark gray. This has worked for years until recently when the pdf viewer switched to light mode again (pic 1). I checked the about:config settings for pdfjs.viewerCssTheme but there appears to be no change. I tried restarting the browser, setting the theme to 0 and to 2 again, updating browser. Sadly the theme is still light gray. Is there a way to change it again? The desired outcome is in pic 2. I do NOT want to change the color of the pdf pages themselves.

I'm having a pretty frustrating developer experience using Firefox to help develop an app that uses Server Sent Events. Now, I'm not sure if I'm the one at fault or if it's something to do with Firefox itself (most likely I'm missing a config option somewhere).

Anways, the issue I'm having is that I cannot seem to be able to see Server Sent Events in the network tab of dev tools. This is specifically what I'm looking for: https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/inspecting_server-sent_events/index.html

I'm testing this functionality by going to https://sse.dev/testpage.html, opening my network tab. I can see the connection to the SSE endpoint however, all I see is "No headers for this request" or "No response data for this request". I know it's getting the data through the event source because I can do stuff with the data. I've also tested this in Edge and everything appears in their network tab as expected which, makes me feel like this is more of a browser-specific issue. Again, I feel like it's me missing a config somewhere or having a privacy setting set which is somehow messing with the event stream.

Any help is appreciated... I guess I got to use Edge for the time being 🤮

Until a week or two ago, Amazon Prime Video worked without a problem on my Firefox browser. Now I cannot get Prime Video to open any show, nor can I access previous episodes of any show. I tried removing all my add-ons, including all my ad blockers and making Prime Video an exception to the enhanced Firefox browser feature. Nothing worked. Can someone at Firefox fix this problem or tell me why it happened? I CAN use prime video without difficulty on Safari and Chrome.

From the subject line - I keep getting this error when trying to use Firefox Sync on my Windows 10 desktop. Sync already works on Mac and Android, and I've already verified that I'm using my primary email to login.

I got an email supposedly from breach-alerts@mozilla.com that claims there are currently 3 data breaches and has this link to resolve: https://blrv1ly5.r.us-west-2.awstrack.me/L0/https:%2F%2Fmonitor.mozilla.org%2Fuser%2Fdashboard%2Faction-needed%3Futm_source=monitor-product%26utm_medium=product-email%26utm_campaign=monthly-report-free-us-scan-no-exp-yes-breach-resolved-no%26utm_content=resolve-exposures-us/1/01010195ceba1024-6e3f74fe-119a-4e2e-9033-398671a830d9-000000/DDeGOTLjROOXCCk2fJvXJbdefc4=419

This seems like a phishing email, is it legit? Should I find another browser?

Hi All,

I would like the content area of my tabs moved up so that the box is filled with the actual tab color, without the white background, and also the text will be vertically centered. Right now, the text is dropping too close to the bottom of the tab.

Had this looking very nice in FF 88 with the same code, as you can see in the attached images, but it seems to render differently in FF 115 ESR and FF 125.

Below is some code I used to style the tabs, but the problem exists without this code as well.

I've also included some "tabs on bottom" code I'm using as well at the very bottom.

Would sure like to get those Classic Toolbar Buttons working again too (shown in the second image), but that will be a later request :)

Any help is appreciated.

Thanks!

/* Highlight non-selected tabs on mouseover */ .tabbrowser-tab:not([selected]):hover .tab-content {

  background-color: #dbe3eb !important;

}

1. TabsToolbar {

 -moz-box-ordinal-group: 3 !important;
 padding-top: 0 !important;
 padding-bottom: 0 !important;
 height: 25px !important;
 background-image: url("bkmr_back.gif") !important;
 border-top: 1px solid #afc0d2 !important;
 border-bottom: 1px solid #8698aa !important;

}

/* Background color of selected tab */ .tab-background[selected="true"] {

   background-attachment: none!important;
   background-image: none!important;
   background-color: #eef5fc !important;

}

/* Background color of non-selected tab */ tab-background:not([selected]) {

   color: #000000 !important;
   background-color: #c7d3e0 !important;

}

/* Border color & bold text for selected tab */

1. TabsToolbar .tabbrowser-tab[selected] {

   font-weight: 700 !important;
   color: #000 !important;
   border-top: 1px solid #8698aa !important;
   border-left: 1px solid #8698aa !important;
   border-right: 1px solid #8698aa !important;

}

/* Border color & normal text for non-selected tab */

1. TabsToolbar .tabbrowser-tab:not([selected]) {

   font-weight: 600 !important;
   color: #000 !important;
   border-top: 1px solid #afc0d2 !important;
   border-left: 1px solid #afc0d2 !important;
   border-right: 1px solid #afc0d2 !important;

}

/* -------------- TABS ON BOTTOM --------------- */ /* TABS: below nav-bar - updated for 89+ | 108+ | 113+ */

• |*:root {

 --tab-toolbar-navbar-overlap: 0px !important;
 --tab-min-height: 25px !important; /* adjust */
 --tab-min-width:  80px !important; /* adjust */

}

1. navigator-toolbox #TabsToolbar {

 position: absolute !important;
 bottom: 0;
 /* height: 27px !important; */
 height: 28px !important;
 width: 100vw !important;

}

/* navigator-toolbox - padding */

• |*:root:not([chromehidden*="toolbar"]) #navigator-toolbox {

 position: relative !important; /*89+*/
 padding-bottom: calc(var(--tab-min-height) + 1px) !important; /*adjust*/
 background-color: var(--toolbar-bgcolor) !important;

}

/* TABS: HEIGHT */

1. tabbrowser-tabs,
2. tabbrowser-arrowscrollbox,
3. tabbrowser-tabs .tabbrowser-tab {

 min-height: var(--tab-min-height) !important;
 max-height: var(--tab-min-height) !important;

}

.tab-stack {

 height: var(--tab-min-height) !important;

}

1. TabsToolbar {

 height: var(--tab-min-height) !important;
 margin-bottom: 0px !important;
 /* box-shadow: ThreeDShadow 0 -1px inset, -moz-dialog 0 1px !important; /*optional*/
 /* background-color: var(--toolbar-bgcolor) !important; */
 color: var(--toolbar-color) !important;

}

/* drag space */ .titlebar-spacer[type="pre-tabs"], .titlebar-spacer[type="post-tabs"] {

 width: 40px;

}

/* Override vertical shifts when moving a tab */

1. navigator-toolbox[movingtab] > #titlebar > #TabsToolbar {

 padding-bottom: unset !important;

}

1. navigator-toolbox[movingtab] #tabbrowser-tabs {

 padding-bottom: unset !important;
 margin-bottom: unset !important;

}

1. navigator-toolbox[movingtab] > #nav-bar {

 margin-top: unset !important;

}

/* hide indicators and caption buttons */

1. TabsToolbar .private-browsing-indicator {display: none !important;}
2. TabsToolbar .accessibility-indicator {display: none !important;}
3. TabsToolbar .titlebar-buttonbox-container {display: none !important;}
4. TabsToolbar #window-controls {display: none !important;}

/* -------------- TABS ON BOTTOM --------------- */

Hi, not sure what I'm doing wrong, but my logins and passwords simply will not synch between devices. I principally use a desktop Win10 machine, and an iOS version of Firefox. Have double-checked settings on both devices, tried forcing a manual sync from each to the other, all to no avail. Any ideas on what I need to do differently? TIA.

Hello Firefox friends o/

Anyone knows how do I make https://yandex.com my default search engine? (in the top bar of the browser). I have attached a screenshot of my settings page. Please have a look at the suspicious lack of an "Add" button 🤔. Despite my efforts, the drop-down menu will not show the available options in the screenshot, you will have to take my word for it, the only available options in that menu are: Google, Bing, DuckDuckGo, eBay and Wikipedia (en).

P.S. The settings page in Firefox must change really often, as I seen so many people suggesting many outdated methods online.

Until today it worked fine. But now whenever I try to login to Xfinity I get You don't have permission to access "http://login.xfinity.com/login" on this server. It works fine on Chrome and Edge. I have disabled my add-ons. I have cleared cache, cookies, etc. I have rebooted. I have turned off firewall. I have checked my DNS. I have changed the DNS protection to OFF in Firefox. I have checked my proxy setting (I have no proxy). I have reinstalled Firefox. Etc. Etc. Nothing works. The fact that it works on Chrome and Edge, that it has worked everyday until today gets me confused. I also tried using my mobile phone as a hot spot to make sure it wasn't related to my Internet connection or IP address. Anyone have any ideas?

I have a very good PC (5800X3D, 7900XT, 32GB DDR4 3600), but Firefox (either the normal, canary and nightly version) can't play smoothly any 4K video (like the Borderlands trailer: https://www.youtube.com/watch?v=lU_NKNZljoQ ). 1440 and lower resolutions are fine, as are 4K videos on Chrome and Edge. FWIW, my CPU during 4K playback is barely used (1-2%), and my GPU's video codec (VCE) is used by around a third. Disabling HW accel makes things better, as it still stutters but it's (barely) passable. I already tried creating a new profile, but still it's the same.

Hello! After a clean install of Windows 11 24h2 Pro, Mozilla Firefox is unusable. It takes about 2 minutes to load a page which is abnormal. I remember I had the same issue when I first installed Windows 11 23H2 Pro and that was resolved somehow but it was 2 or 3 years ago and I've no idea what the solution was back then. I've tried some basic stuff including Test suggestion which of course didn't resolve anything as almost all of them are referring to cleaning cache, reinstall Firefox etc and it literally has nothing to do with my situation. Any solutions?