Type about:addons<enter> in the address bar to open the Add-ons Manager. Hot key; <Control>(Mac=<Command>) <Shift> A)

On the left side of the page, select Plugins. Make sure the ones you want to use are set to Ask or Allow.

Go to the web page. Once the page is loading, mouse to the address bar and Left click the icon. Select Permissions. In the menu, Make sure the ones you want to use are set to Ask or Allow.

I did what suggested, but it doesn't work. I suspect that, at this point, the security of the site could be the problem. I attach the parameters. Where I can force an "allow" about security? Thanks a lot.

I did what suggested, but it doesn't work. I suspect that, at this point, the security of the site could be the problem ("Connection it's not secure"). I attach the parameters. Where I can force an "allow" about security? Thanks a lot.

The video now are working, and I didn't new changes. Apparently it was a site problem, now solved. Thanks.

That's good to hear. Please flag your last post as Solved Problem so others will know.