Try to toggle DRM off/on to see if that makes Firefox load these components.

   Options/Preferences -> Content: Play DRM 

What do you see in about:addons -> Plugins?

Thank you ! But the deactivation / reactivation of DRM is still not positive for loads ... And Firefox support does not know the word "addons", nor the word "PUGGINS"! Too complicated for me, simple individual. thanks anyway cordially Daniel

hello....

Turn off private browsing

• Close the Firefox browser and reopen it.
• Try Netflix again.

Enable cookies in Firefox

• Select the Menu icon menu from the upper right corner.
• Select Options.
• Select Privacy & Security from the menu on the left.
• Under History, locate the Firefox will: drop-down menu and select Remember history.
• Close the tab and try Netflix again.

Ensure DRM content is enabled

  1  Select the Menu icon from the upper right corner of your browser.
  2  Select Options.
  3  Select Content from the menu on the left.
      * If you do not see Content, select General and scroll down to Digital Rights Management (DRM) Content.
  4  Uncheck, then recheck the box next to Play DRM content.
     *  If the box next to Play DRM content was not checked, check it before continuing.
  5  Restart Firefox and try Netflix again.

Update Firefox's content protection feature

  1  Select the Menu icon from the upper right corner of your browser.
   2 Select Addons.
   3 Navigate to the Plugins tab.
   4 Find the Widevine Content Decryption Module provided by Google, Inc., right-click on it, and select Find Updates.
      * If you see the message Widevine Content Decryption Module provided by Google, Inc will be installed shortly, you may need to wait a moment for it to install.
   * Ensure Always Activate is selected from the drop-down menu next to the Widevine Content Decryption Module.
   5 Try Netflix again.

Update Firefox

• Select Firefox from the menu bar.
• Select About Firefox. This will check for updates and download any that are available.
• Once updates are complete, select Restart Firefox to Update.
• Try Netflix again.

tell me its help then mark solution.

thank you and regards,

Arman

... And Firefox support does not know the word "addons", nor the word "PUGGINS"! ...

And plugin with an L and 1 G. But kinda a moot point. All plugins are gone from Firefox, and Adobe Flash will probably be gone by year's end; and now it has to be activated each time it is needed, to prepare users for the upcoming ultimate end of Flash.

Can't offer advice about Netfilx, don't use it as my needs are simple.