Sitemap Not found (404 Not Found)

I've Installed Infinite SEO 1.3.5 on my multisite 3.2.1 website, network activated it, but the "Path to the XML Sitemap" was blank, so I manually added the path to xml sitemap which is "/var/www/vhosts/mydomain.com/httpdocs/wp-content/blogs.dir/1/files/sitemap.xml", but when I click http://mydomain.com/sitemap.xml it gives me 404 Not Found error.

I checked inside the folder blogs.dir/1/files/, the sitemap.xml and sitemap.xml.gz are already created.

What am I missing here?