Sometimes, the video or audio content in a web page cannot be properly downloaded or played in Firefox. This article will help you solve these problems.

Reload the website

Sometimes a change you make in the system settings, such as selecting another sound device in the Volume Mixer, may not be applied correctly in an already open tab. Try reloading the website to see if it solves the issue.

Allow autoplay of media with sound

Firefox may be blocking media with sound from playing automatically. To allow media autoplay, see Allow or block media autoplay in Firefox.

HTML5 audio and video

Firefox has built in support for open media formats usually associated with MP3, WebM, Ogg, and Wave containers. However, MP4 containers usually depend on platform decoders for AAC and H.264 audio and video streams. For more information, see HTML5 audio and video in Firefox.

Digital Rights Management (DRM) protected videos

If you have problems playing DRM-controlled content from Amazon Prime, Netflix, Hulu, Disney+ and other streaming services, make sure that your Firefox Settings General panel Digital Rights Management (DRM) Content setting, Play DRM-controlled content is check marked and that the Google Widevine plugin is enabled. See Watch DRM content on Firefox for more information.

Clear the cache

See How to clear the Firefox cache.

Disable interfering extensions or ad-blocking software

Ad-blocking software, such as anti-banner filters of your Internet Security program, or extensions, such as uBlock Origin or Adblock Plus, can prevent audio or video content from playing.

• If the site works with ad-blocking disabled, you may want to add the site to your whitelist in your adblocker filter.
• If the video or audio plays when you disable all extensions, then one of your extensions was causing the problem. For more information, see Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems.

Check some Firefox settings

• Cookies:
  1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
  2. Select the Privacy & Security panel and go to the Cookies and Site Data section.
  3. Verify that cookies are enabled and that the site is not blocked in the Exceptions list.
• History:
  1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
  2. Select the Privacy & Security panel and go to the History section.
  3. Make sure that Firefox is set to Remember history.
• Pop-up windows:
  1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
  2. Select the Privacy & Security panel and go to the Permissions section.
  3. Allow the website as an exception to the Block pop-up windows setting.

Reset preferences

See Reset Firefox preferences to troubleshoot and fix problems.

Remove specific entries in the hosts file (advanced users)

If you use a hosts file, you can temporarily disable it by renaming it Xhosts. Or, you can edit the hosts file to remove specific entries that may be causing videos on certain sites to fail (see this thread for an example). To apply changes to your hosts file, you may need to flush the DNS cache by entering the command: ipconfig /flushdns in the Run dialog box on Windows.

Related links

• What to do if Firefox won't play any sounds
• Manage file types and download actions in Firefox
• Mixed content blocking in Firefox

Based on information from Video or audio does not play (mozillaZine KB)