UPFRONT INACTIVE TOO MANY TIMES

Dear Support Team,

This is problem I am facing for a relatively long time, on all my websites. At the beginning, I thought it was a temporary issue, however, it is continuing to bother me

Namely, when I want to edit my site via Upfront the following two things happen:

1) If I click "Upfront" button in the upper left on the Wordpress dashboard next my front page opens, but not in an "edit mode", so I cannot use Upfront.
2) If I open a page/post and than try to edit in Upfront, than the Upfront button is gray and inactive, i.e. in-clickable

I have tried with logging out, clearing cache of my site, clearing browser cache and the results are more in favor of not sorting the problem out, i.e. the Upfront keeps being inactive.

Could you please help,
Vladimir