Each time I use Layout builder (both archive and single), after a couple of actions (changing colour, text, etc) cornerstone crashes. By refreshing the browser I get a browser error (bellow) and have to go back to wp backend.
Not Found. The requested URL was not found on this server. Additionally, a 404 Not Found error was encountered while trying to use an Error. Document to handle the request.
I have everything up to date (wp, theme, plugins, PHP, server memory) and it was working fine not a long ago.