SSL certificate problem

I’m working on a Lenovo-PC-S510p Intel Core i7-4500U CPU with Windows 10 Pro - 22H2 - 64 bit
Avast Premium Security 24.11.9615a
I’m enabled to surf any kind of website, but disabled on an Italian State website regarding professional acknowledgement and training, on which I find a block due to “SSL certificate problem: self signed certificate in certificate chain”.
I tried disabling firewall, but no way.
What can I do??

Try sending a form to the Avast team through this link: Choose Your Sample Submission Type | Avast

The team will be able to check on this matter.
It may be that the certificate is from an unauthorized provider.

I find a block due to “SSL certificate problem: self signed certificate in certificate chain”.

Can you post a screenshot of the error message, as I’m not sure this is an Avast alert more possibly a block by the website on avast.