It is definitely not Gutenberg. when I write a new post, there used to be a field below it where I could choose the header image, now only the header image settings remain, but no option to choose it.
I have made a screenshot of that section https://postimg.cc/XGC9TT0R
I am not really familiar with all this, I just got this page dropped on me to look after, but this issue is really bad, because new posts only get gray background.
the website is http://www.lbba.lt
Thanks
