Thanks for your answer
That issue is really important to me so please let's try once more and if no solution I give up.
By default tags for portfolio does not exist on this theme so thanks to Dude:
I open up includes\admin\register-portfolio.php and replace:
At that point I can add tags to portfolio. I also used a plug-in to add tag to pages.
I add 1 post, 1 page and 1 portfolio with the tag 'fred' . Then I tried different plug-in include the one you mentioned and also few tag cloud plug-in. I also tried with different version of wp, disable other plug in....
Most work fine and show result for page and post, but no one show result for portfolio, that is the real problem !