Hello,
in Enfold Advanced Styling menu I chose to edit H4 element. And then I used drop-down lists to choose a Font and its Weight:

I do not know where Enfold loads these fonts from. Custom font I really wanted was Franklin Gothic Heavy, but it was not in the list. Source Sans Pro seemed to be the most similar alternative so I picked it and then selected the weightest variant that was offered by the drop-down.

I tried to change Weight to 800, but nothing changes on my webpage, it still looks like it looks, no heavier weight. Strange.

That is the problem — It happens every now and then, but completely by itself.
I do absolutely nothing with the website. Sometimes you see the eshop page normally with products and other times you see it empty like I sent you on the picture. And again and again.