Flash Player not working

Some websites still use flash player for videos. But obviously flash player is not working. Synaptic Package Manager shows me that “pepperflash plugin - nonfree” and “browser - plugin - freshplayer - pepperflash” is installed. My browser is Vivaldi recent version.
What can I do to make flash player working?
Kind regards,

Installed pepperflashplugin-nonfree aswell as vivaldi freshly here and it works just fine.
However it asks me on the flash testing site if I want to enable flashplayer and I have to hit allow.
Maybe it is set to denied for whatever reason or you did not see the question popup box in the top right corner.
You can click however on the far left besides the url to list all the plugins and settings for that particular website. There should be a flash option which allows setting to allowed for this website.
If you change this setting you need to reload the website and flash should work.

Hi leszek,
Thank you for the advice.