Hi rudeger1,

Sometimes Refreshing the Browser can fix many problems.

Try Refreshing your Browser:-

• To do this, click the menu button at the top right corner of the Firefox window.

• Click the “Help” option near the bottom of the menu.

• Click the “Troubleshooting Information” option in the Help menu.

• Click the “Refresh Firefox” button at the top right corner of the Troubleshooting Information page.

• You’ll be warned that this will remove your browser add-ons, reset your customizations, and revert other browser data to the default settings. Click “Refresh Firefox” to confirm you want to make these changes.

If it doesn't solved your problem, then feel free to ask in Reply Section. Thanks for raising your question in Mozilla Support Forum.

Thanks for that,but that didn't work.

hello rudeger,

maybe the firefox useragent (the information the browser sends to websites to identify itself) got overwritten or corrupted - please refer to the following article on how to reset it: https://support.mozilla.org/en-US/kb/websites-say-firefox-outdated-or-incompatible#w_other-causes

Hope this help you. Thank you

Are you possibly using Private Browsing mode ?

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

You can also try to disable Tracking Protection.

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop

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You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.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 for websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences).

"Remove the Cookies" for 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

Hello,

The Refresh feature (called "Reset" in older Firefox versions) can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information.

Note: When you use this feature, you will lose any extensions, toolbar customizations, and some preferences. See the Refresh Firefox - reset add-ons and settings article for more information.

To Refresh Firefox:

Open the Troubleshooting Information page using one of these methods:

• Click the menu button New Fx Menu , click help Help-29 and select Troubleshooting Information. A new tab containing your troubleshooting information should open.
• If you're unable to access the Help menu, type about:support in your address bar to bring up the Troubleshooting Information page.
• At the top right corner of the page, you should see a button that says "Refresh Firefox" ("Reset Firefox" in older Firefox versions). Click on it.
• Firefox will close. After the refresh process is completed, Firefox will show a window with the information that is imported.
• Click Finish and Firefox will reopen.

Did this fix the problem? Please report back to us!

Thank you.

Sorry to say it did not!