Invalid nameservers

Hi, I’m trying to connect my domain (.it) to Cloudflare. The domain is hosted on an Italian hosting called Aruba. When I try to enter nameservers, a message says that the nameservers are not valid. I have checked several times and I’m sure they are right. I have already activated a site with CloudFlare (another .it) with the same provider without problems (the Nameservers were the same). How can I solve the problem? Thanks for the support

Common issue with the Italian registry. The search has more on it