Thank you for your reply! This site has been inactive for a while, and yesterday when I was trying to log on, I realized the whole page, including my user was gone. I managed to log in creating a new user in phpAdmin, on my one.com panel. The only thing left on my page was the theme installed, everything else was emptied, content, plugins, the works. So I just started to make some random posts to start the page over. I updated everything today, so the theme and wordpress is the latest version. I installed the Gutenberg plugin, because I thought that was the issue, then I installed the AFC Blocks plugin after that. The only thing that changed, was that the “add new block” + turned into a blue squere that reacted to a click, but still nothing happened when I clicked it. Before I installed the plugin, the + symbol was “flat”, unclickable. I am not able to create new blocks by using the keyboard shortcuts either.
I’ve tried both Opera and Chrome, issue remains the same. I have another wordpress – page, that does not have this issue on these browsers, same theme. (But not updated to latest version, though)