hello Moilleadoir... you please try these steps...

   *  In the drop-down, click the option called Add-ons.

• Of the options on the left side of the screen, choose Plugins. ...
• Scroll down the list of Plugins until you find Shockwave Flash (this is another name for Flash Player).
• The enable Flash, click the drop-down box on the Shockwave Flash plugin and choose Always Activate.

Does that mean you can’t save permissions per site any more?

yes it mean you can’t save permissions per site any more.

Hello,

You can't set   "Shockwave Flash"   to  "Always Activate"   anymore;   you can only click "Allow" when a site asks you to activate Flash.

It's the end-of-life for Flash at the end of this year (which was anounced by Adobe a long time ago).

Please see this thread :

https://support.mozilla.org/bm/questions/1268168

Hello..

A change in version 69.0, as part of phasing out Flash, is in the Release Notes:

"As previously announced in the Plugin Roadmap for Firefox, the "Always Activate" option for Flash plugin content has been removed. Firefox will now always ask for user permission before activating Flash content on a website."

You can view the full What's New In Firefox! here: https://www.mozilla.org/en-US/firefox/69.0/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-browser&utm_campaign=whatsnew

Such choices are saved as part of the Site Preferences.

In case you use "Clear history when Firefox closes" or otherwise clear history.

   do not clear the Site Preferences 

   Options/Preferences -> Privacy & Security
   Firefox will: "Use custom settings for history":
   [X] "Clear history when Firefox closes" -> Settings
   https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox 

   clearing "Site Preferences" clears exceptions for cookies, images, pop-up windows, and software installation and exception for password and other website specific data
   clearing "Cookies" will remove all selected cookies including cookies with an "Allow" exception you may want to keep

choose Always Activate.

You can only choose either   "Ask to Activate"   or   "Never Activate"   (sorry .... )