Hello,

Sometimes Refreshing the browser can fix many issues.

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.

Refreshing Firefox {web link} is a LAST RESORT ! !

Refreshing Firefox -- easily fix most problems

If you're having problems with Firefox, refreshing it can help. The refresh feature fixes many issues by restoring Firefox to its factory default state while saving your essential information like bookmarks and open tabs. Everything else, like user settings and add-ons, are removed.
Note: Refresh saves your old profile to the desktop in a folder called Old Firefox.

Many site issues can be caused by corrupt cookies or cache.

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

If there is still a problem, Start Firefox in Safe Mode {web link}
by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh).
Did this help?

While you are in safe mode;

Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches.

How to disable Hardware Acceleration {web link}