Our dear user @YacineBoussoufa reported that you cannot access the non-www version of the Wikimedia Italia website:
Websites prove their identity via certificates, which are valid for a set time period. The certificate for wikimedia.it expired on 10/17/2020.
― https://wikimedia.it/
This should be fixed because some people access the website manually typing the URL without www and should not see a very-big and scaring warning about the kidnapping of your browser ecc.