Make sure you are not blocking content.

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

One issue that seems more common lately is Firefox's Tracking Protection feature. When it is blocking content in a page, a shield icon will appear at the left end of the address bar next to the padlock icon. This article has more info on managing this feature: Tracking Protection {web link}

https://support.mozilla.org/en-US/kb/what-happened-tracking-protection?redirectlocale=en-US&redirectslug=tracking-protection

https://support.mozilla.org/en-US/kb/content-blocking

Hi Fred,

Thank you for your response. Unfortunately neither of these solutions fixed the issue.

I tried starting Firefox in safe mode, but I am still getting the same errors.

Also, there is no "tracking protection" shield icon at the left end of the address bar. There is only the green padlock and the grey chain-link indicating DRM content.

Please let me know if you have any other suggestions before I do a refresh.

Make sure that DRM is enabled and that the Widevine plugin is installed and enabled.

Try to toggle DRM off/on to see if that makes Firefox (re)load DRM components.

• Options/Preferences -> General: Play DRM
• https://support.mozilla.org/en-US/kb/enable-drm

Hi Cor-el, I addressed both of those possibilities in my post.

I have already toggled DRM on/off and restarted Firefox, many times. The Widevine plug-in is installed, enabled, and updated.

Any luck on this website?

• https://shaka-player-demo.appspot.com/

Make sure you do not run Firefox in permanent Private Browsing mode (Always use Private Browsing mode; Never Remember History).

• https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history

• Options/Preferences -> Privacy & Security
  Firefox will: "Use custom settings for history"
• remove checkmark: [ ] "Always use Private Browsing mode"

This issue can be caused by corrupted cookies or cookies that are blocked.

• check the permissions for the domain in the currently selected tab in "Tools -> Page Info -> Permissions"

You can try these steps in case of issues with web pages:

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• hold down the Shift key and left-click the Reload button
• press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• press "Command + Shift + R" (Mac)

Clear the Cache and remove the Cookies from websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences).

"Remove the Cookies" from websites that cause problems:

• Options/Preferences -> Privacy & Security
  Cookies and Site Data -> Manage Data

"Clear the Cache":

• Options/Preferences -> Privacy & Security
  Cookies and Site Data -> Clear Data -> Cached Web Content: Clear

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Hi Cor-el, thank you for these suggestions. The shaka-player-demo website you provided gave me the message that my browser is not supported.

I have checked my privacy and security setting and confirmed that Firefox is not set to always run in private browsing mode.

As for page permissions, I check and every box is set to "use default."

Reloading the webpages while bypassing the cache did not solve the issue.

I have cleared my entire cache and cookies many times while attempting to fix this issue, it has never worked.

Regarding the theme, I did have it set to Light, but I've changed it back to Default on your suggestion, and unfortunately it has not fixed the issue.

I have already started Firefox in safe mode, it had no effect on the issue.

Does the Web Console give more detail about what is wrong?

• "3-bar" menu button or Tools -> Web Developer
• https://developer.mozilla.org/en-US/Tools/Web_Console

I tried it on Netflix. It says "unreachable code after return statement" over and over again, in relation to something called cadmium-playercore. Here is the info from Firefox help pages:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/Stmt_after_return?utm_source=mozilla&utm_medium=firefox-console-errors&utm_campaign=default

That's the only error or warning it gives.

I've attached a screenshot of the error messages for HBO Now.

Try the 'Learn More' link. Anything there?

This last screenshot would suggest that Firefox gets an HTML error page (Content-Type text/html) for the requested media.

Do any server requests show if you enable XHR and Requests in the Console ? See also the Network Monitor (XHR, Media, Others).

• https://developer.mozilla.org/en-US/Tools/Network_Monitor

You can check the media.mediasource prefs on the about:config page and reset any that appear user set (bold) via the right-click context menu to the default value.

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

Does the YouTube test page show at least that you have proper support for playing media files via the HTML5 media player?

• https://www.youtube.com/html5

You can check for problems with preferences.

• delete possible user.js and numbered prefs-##.js files and rename/remove the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases
• http://kb.mozillazine.org/preferences_not_saved
• http://kb.mozillazine.org/resetting_preferences

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

You can create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Well, Cor-el, you fixed the issue.

Media.mediasource.enabled was set to false. I reset that, and now all the streaming services are working.

I'm not sure how that happened, as I've never been in the about:config before, but thank you very much. I really appreciate your help and patience.

You're welcome. The screenshot you posted helped to identify a possible cause.

This should have happened a long time ago if you haven't been able to play these media files for two years. Maybe next time not to hesitate that long to ask for support :wink:

Thank you all helpers but it is my impression Firefox does not support streaming since Edge and Chrome offer me no problems. I have tried all suggestions provided here and else and no fix so far. I much prefer using Firefox than any other browser for reasons most know but I am forced to use Chrome if I want to stream. My problem is with the latest version of Win7, Portege z395-300 laptop. Thanks! Isis Mc