If clearing the cache did not solve the issue, there are a few other things you can try:

Disable any extensions you have installed in Firefox. Sometimes extensions can cause conflicts with websites, and disabling them can help narrow down the cause of the problem.

Reset Firefox to its default settings. This will remove any customizations you have made to Firefox and restore it to its default state. To do this, go to the Firefox menu, click on Help, then click on Troubleshooting Information. In the Troubleshooting Information page, click on the "Refresh Firefox" button.

Disable hardware acceleration. Sometimes hardware acceleration can cause issues with websites. To disable it, go to the Firefox menu, click on Options, then click on General. Scroll down to the Performance section and uncheck the box next to "Use recommended performance settings". Then uncheck the box next to "Use hardware acceleration when available".

If none of these solutions work, you can try uninstalling and reinstalling Firefox to see if that resolves the issue.

Adblock was causing problem.

Turned it back on and no problem so far ???