This .htaccess file looks like it is for a network that uses sub-folders but the URL address that you say you are trying is for a network that uses sub-domains. Which type are you using? Have you followed the steps in the /wp-admin/network/setup.php page correctly?
Another idea is that you have added SSL but the site is maybe still using the old http URL addresses. Click edit on one of the sites to see the Site Address (URL) field. Does it have https there or just http?