You may ask why, but having problem with VisualEditor in latest 1.35 MediaWiki, since it does not like Private mediawiki sites. You have to log on to view site "$wgGroupPermissions['*']['read'] = false;". (Ref: Topic:Vuonx6s9lxsy1xew)
With such sites you can not edit pages (like I am doing now). Currently the only real workaround is to test IP address in LocalSetting.php but no help if you want to access site from many clients. This is why I am asking if there is something I can add in LocalSettings.php which test if Username/password is valid, so then I can set $wgGroupPermissions['*']['read'] = true;"