The Twitter media could not be played error on the Mozilla Firefox browser may be fixed by allowing autoplay of media with audio on the browser. Depending on the cause, the problem could also be resolved by disabling the interfering extensions, and ad-blocking software or by just clearing the browser cache. 

In advanced cases, you may need to reset your Firefox browser preferences, or even remove specific entries in the host file. This error message is often displayed when the media content cannot be downloaded and displayed properly. 

This guide will help you understand what causes this problem. Additionally, it includes a number of methods you can apply to fix the “media file could not be played” error on Windows, Mac, and Linux. 

Twitter Videos Not Playing Firefox Causes 

The inability of the Mozilla Firefox browser to display Twitter videos, or any other platform, maybe as a result of different things. The “media could not be displayed” error is prevalent on the Firefox, and Chrome browsers, regardless of the device you are using. 

Whether you are using the Firefox browser on an Android, iOS, Window, or Linux device, here are some of the common causes of this error: 

Internet Connectivity Problem 

You will not be able to load or even play Twitter videos on Firefox, or any other browser, when the connection is slow or when experiencing an outage. In such a case, the browser will continue to show the loading symbol for a longer period than expected. 

Conflicts with Extensions and Ad-Blocking Software 

The extensions, such as Adblock or Flashblock, and ad-blocking software like anti-banner filters may also prevent Twitter video and audio content from loading on Firefox. In this case, you should try to play the problematic content with the ad-blocking software disabled. 

You should also try to load the Twitter video with the Firefox extensions disabled to see which of them may be causing the problem. 

Incompatible Twitter Video Format 

If you can play all the other videos on Twitter, except one or several, then the problematic videos may be in a format that is not compatible with Firefox. Basically, Twitter supports MP4 video content in the H264 format and audio in the A64 format for web browsers.

In Mobile applications, Twitter supports both MP4 and MOV video formats. The Mozilla Firefox browser, on the other hand, offers support for media formats that are associated with Ogg, Wave, WebM, and MP3 containers. 

However, MP4 containers on this browser normally depend on platform decoders for H.264, and AAC video and audio streams. If such decoders are not available on your device, you may be unable to play some videos and audio files on Twitter. 

Inappropriate Firefox Settings 

If not configured properly, the pop-up, cookie, and history settings on your Firefox browser may also prevent Twitter videos from playing. In this regard, you should ensure that the Twitter site is not blocked in the Exceptions list and that cookies are enabled. 

Additionally, ensure that the browser is configured to remember history. You should also add the Twitter site as an exception to the ‘Block pop-up windows’ settings, as elaborated later in his guide. 

Flash Plugin Missing

Although Firefox will be ending Flash support at the end of 2020, all the current versions require a Flash plugin to play embedded audio and video files. If this plugin is missing, or disabled in the Add-ons Manager, you may be unable to play Twitter videos. 

Proprietary Codecs Missing 

In addition to the above-discussed causes, the “Twitter videos not playing” error on Linux distributions may also be triggered by the lack of proprietary codecs. 

How to Fix the Twitter Videos Not Playing Firefox 2020 Issue 

Sometimes, the audio or video content on the Twitter webpage may fail to load and play as expected on the Mozilla Firefox browser. In most cases, the problem is caused by a slow internet connection or an internet outage. 

As such, you need to check your internet connection before trying the advanced solutions discussed in this guide. To do this, try launching other applications that require internet access and check whether they are working as they should. 

If the internet connection does not seem to be the problem, you may use the following methods to troubleshoot and fix the “Twitter the media could not be played” error on Firefox: 

Method 1: Disable Firefox Hardware Acceleration

Hardware acceleration is a great feature that helps enhance video clarity. However, it may become buggy at times, hence trigger the Twitter videos not playing issue. This method requires you to restart the browser and may cause you to lose important data.

As such, it is advisable to first save your work and bookmark important tabs. Once done, click on the three-bar Menu icon, positioned in the top-right corner of the Mozilla Firefox browser window. Next, select Options from the menu that comes up. 

Scroll down the options list, and select the Performance options. Uncheck the box adjacent to ‘Recommended Settings’. This will display the option to disable/enable Hardware Acceleration, which you need to uncheck as well. Restart the browser and try playing Twitter videos.

Method 2: Allow Autoplay Of Media With Sound

By default, the Firefox browser is designed to block media with sound from automatically playing. If you wish to have videos play automatically on the browser, you need to change the autoplay settings accordingly. 

The following procedure will help you achieve this:

Step 1: Open Firefox Autoplay Settings 

To do this, launch the Mozilla Firefox app on your computer and click on the three-bar Menu button, in the top-right corner of the window. Now select Options, and then navigate to the Privacy & Security panel> Permissions section. 

Alternatively, you could just search for autoplay using the Find in the Options search box. Now click on the Settings button next to Autoplay.

Step 2: Configure Autoplay Settings 

Click on the ‘Default for all websites’ heading to expand a drop-down menu that allows you to choose how Firefox should handle media autoplay. You need to change this choice from the default ‘Block Audio’ selection that is preventing the autoplay of Twitter videos.

Instead, choose the ‘Allow Audio and Video’ selection from the drop-down menu, which allows all media to autoplay. Once done, click on the ‘Save Changes’ button to apply the changes you just made. Close the window and re-launch the browser. 

Method 3: Clear Firefox Cache

In an effort to speed your browsing experience, Firefox automatically stores the images, scripts, and other important aspects of the websites you visit. If the cached files on Firefox happen to be corrupted, you may be unable to play Twitter videos on the browser. 

To fix such a problem, you need to clear the cache, and probably the browsing history as well. Launch the Firefox browser, click on the three-bar Menu button, and then select Options. Next, select the Privacy & Security panel, and navigate to the ‘Cookies and Site Data’ section.

Click on ‘Clear Data’, and then uncheck the ‘Cookies and Site Data’ option. With just the ‘Cached Web Content’ option checked, click on the Clear button. Close the window, and relaunch the browser to check whether the problem has been fixed. 

Method 4:  Fix Twitter Video Compatibility Problem 

The Windows Media Player and media-related technologies required by the Firefox browser to decode and play certain video formats may be missing on your Windows OS. This often happens following an update of the Windows operating system. 

To fix this problem, Microsoft offers a Windows Media Feature Pack, especially for the KN and N editions of the OS. You need to download and install the newer version of the feature pack after you have updated the OS (even if you had the feature pack installed in the previous OS version). 

In the 1903 and later versions of Windows 10, the latest Media Feature Pack can be added as an Optional Feature. To do this, navigate to Start > Settings > Apps > Apps and features > Optional features > Add a feature. From the list of available optional features, find and select the ‘Media Feature Pack’.

Method 5: Configure Firefox Settings Accordingly 

If not configured properly, the history, cookies, and pop-up settings on the Firefox browser can also prevent Twitter videos from playing. To change these settings, click in the three-bar Menu icon in the top-right corner of the Firefox window and select Options. 

Now select the ‘Privacy & Security’ panel and navigate to the History section. Ensure that the browser is set to the ‘Remember history’ selection. Return to the ‘Privacy & Security’ panel, and open the ‘Site Data’ section. Ensure that cookies are enabled and that Twitter is not blocked in the Exceptions list.

Return to the ‘Privacy & Security’ yet again, and navigate to the Permissions section. Under the ‘Block pop-up windows’ settings, ensure that the Twitter website is set as an exception. Once done, close the window and relaunch Firefox.

Method 6: Disable All Extensions

As mentioned earlier in this guide, browser extensions and add-ons can also cause the ‘Twitter media could not be played’ error. To check whether this is the problem, you need to disable all your installed extensions, as follows: 

Step 1: Click on the three-bar menu button on the Firefox browser, and select Extensions. This will display a list of the extensions currently installed on your computer. 

Step 2: Select each extension individually and then click on the blue toggle button adjacent to it to disable it. The extension will be moved to the disabled list automatically. Repeat this step for each extension on the list to disable them all. 

Step 3: Once you have disabled all the extensions, click on the menu button once again and select Exit to close the browser window. 

Relaunch the Firefox browser and check to see whether you can play Twitter videos. If the problem has been fixed, then the problem was one of the extensions on your browser. In this regard, you need to enable each of the extensions individually to identify the one that is causing the problem. 

How to Test for the Faulty Extension on Firefox 

To single out the problematic extension, you need to re-enable the extensions you disabled in the above steps one after the other. Launch the Firefox browser on your computer, click on the three-bar menu icon, and then select the Add-ons option. 

Select one extension at a time, and then click on the toggle button to enable it. Once enabled, the toggle button should turn blue. Restart the browser and check whether you can play Twitter videos. If the browser is still playing Twitter videos, the extension you just enabled is not the problem. 

Repeat the above-discussed steps to enable each of the extensions, until you start getting the media could not be played error message. Now that you have identified the extension that is preventing Twitter videos from playing, you should just disable or uninstall it altogether. 

Method 7: Install/Enable Flash Plugin

The Mozilla Firefox browser uses the Flash plugin to play embedded audio, and videos on some websites, including Twitter. If the Flush plugin is not available, you may have problems playing Twitter videos on Firefox. In this case, you will get this error message: “A plugin is needed to display this content”.

If you are getting such an error message, you do not have the Flash plugin installed on your computer. To fix the problem, you need to install the right Flash plugin version, as explained in this guide. If you have the Flash plugin installed, you may encounter the Twitter media could not be played error because the plug-in is disabled in your Add-ons Manager.

To enable it, launch the Firefox browser, and click on the menu button in the top-right corner of the window. Next, select the Add-ons option, and then select Plugins. Select the Flash plugin, and click on the ‘Never Activate’ option. Now select ‘Never Activate’ from the drop-down menu.

Method 8: Allow Plugin Container in Your Internet Security Program

A conflict between your Internet Security software and the Firefox Plugin Container can also trigger the Twitter videos not playing problem on Firefox. If you think that this is the problem, you should just whitelist the Firefox Plugin Container in the Internet security software. 

If you are using Windows Firewall as the default Internet security software, here is how you should configure its settings to fix the problem in Windows 10: 

Step 1: Launch Windows Firewall 

Press the Windows button on the keyboard to display the Start Menu, and select the Control panel. Open the “System, and Security” category on the Control Panel window, and then select Windows Firewall.

Step 2: Change Windows Firewall Settings 

On the Windows Firewall window, click on the ‘Change Settings’ button, and find Mozilla Firefox on the list of programs displayed. 

Click the Change Settings button, and try to find Mozilla Firefox (or firefox.exe) on the list of programs displayed. If you find it, select it, and click on the Remove button. If prompted, confirm that you want to remove the entry. Next, click the ‘Allow another program’ button to display the ‘Add a Program’ window. 

Click on the Browse link on this window, and navigate to the Firefox program directory (usually C:\Program Files\Mozilla Firefox\). Double-click on the firefox.exe file, and then click on the Add button. Finally, click on OK to save the changes and close the window. 

Method 9: Reset Firefox Preferences

The Refresh functionality on Firefox restores that browser to its default settings and allows you to save essential user information. If the other solutions discussed in this guide have failed to fix the “Twitter videos not playing” error, resetting your browser preferences is likely to work. 

This method is aimed at removing all the customizations you have on the Mozilla Firefox browser, including added themes and extensions.  To do this, launch the Firefox browser, click on the three-bar menu icon, and select Help. Next, select the ‘Troubleshooting Information’ option.

From the right side, click on the ‘Refresh Firefox’ option, and confirm the operation by clicking on ‘Refresh Firefox’ once again. 

Alternate Method: Delete Firefox Preference Files

Alternatively, you could Reset Firefox preferences by deleting your preferences files manually. Here is how you should go about this: 

Step 1: Launch Firefox, click on the menu button, and select ‘Troubleshooting information’ to open the Troubleshooting information tab. 

Step 2: Navigate to the ‘Application Basics’ section, located next to the Profile Folder, and click on ‘Open Folder’. Once you have opened your profile folder, click on the Firefox menu button and select Exit. 

Step 3: Locate the prefs.js folder and delete or rename it to something else, such as prefs.jsOLD, if you wish to keep the old file as a backup. If you happen to have multiple prefs files in the profile folder, you need to delete or rename the prefs.js.moztmp file as well. 

Step 4: Close the profile folder, and launch the Firefox browser to check whether the error has cleared

Method 10: Installing Additional Codecs (Linux-specific Solution)

If you are using a Linux-based operating system, such as Ubuntu or Linux Kamarada, the Twitter videos not playing problem may also be as a result of missing codecs. Ubuntu, for instance, does not come with an automatic codec installation system. 

As such, Twitter videos may fail to download and play on the Firefox browser on such a computer. To fix the error, you need to install the required codecs manually on your Linux distribution. For Linux Kamarada users, you can resolve this issue by adding the Packman repository to your system. 

Next, you need to refresh the list of available packages from online repertories, and then update the system packages. While doing this, you should allow vendor change, allowing some openSUSE packages to be replaced with Packman (which has the missing codecs).

Final Verdict 

As essential as they may be, Twitter video and audio files may fail to download and play on the Firefox browser, regardless of the operating system you are using. This may be caused by extensions, and ad-blocking software, wrongly configured Firefox settings, or even missing codecs in Linux. 

The appropriate solution for the problem will depend on the actual cause of the error. The methods discussed in this guide will help you fix the Twitter videos not playing issue on Windows, Ma, and Linux systems.