If you set up a new wiki with MediaWiki 1.35 (since it adds the PHP-based Parsoid server), and you get this error trying to load VisualEditor:
Error contacting the Parsoid/RESTBase server: (curl error: 28) Timeout was reachedIt’s because the server is trying to contact itself with the server name (hostname/IP). If it’s a DNS name, then make sure the name it uses resolves to itself; a quick fix was to add it to the hosts file.