Thank you, @mazedulislamkhan
1. Yoast triggers the problem, no doubt.
2. No conflicts.
3. No javascript errors explicitly mentioning Yoast but I haven’t got enough knowledge to know if any of the errors there are related to Yoast in spite of not showing the word” name “Yoast”.
So, this is way too much for me, and I’m not the type of user that buys premium in order to (possibly) solve an issue found while using the free version. I always (almost) start with free and move forward to premium because I’me satisfied, not because I have to solve a problem.
I’m sorry for that, in this website Yoast will have to be dismissed.
For the sake of honesty, I’m not saying that Yoast is to blame for the problem. It may be something with the theme or with the hosting, but…
Thank you anyway,
Jo?o silva