@ilBigo @mariobros AFAIK, you cannot verify your blog which is hosted on a subdomain of a blogging platform such as altervista, blogger/blogspot, etc because you have no direct access to the root directory or the DNS records.
There is of course a workaround for this but would cost you some $$. You can buy a custom domain for your blog. In this way you have full authority/access to modify the DNS records of your very own domain.
There are many domain registrars that offers cheap domain registration for different domain extensions. If you’re serious in blogging, I recommend going for a TLD extension such as .com, .net, and .org.