The domain atb.bergamo.it has the proxy activated but the browser told me that the SSL certificate is expired.
The encryption mode is set to flexible and I added the rule to always use https.
Can you help me?
Another consideration is the 4° level of www.atb.bergamo.it, does Cloudflare support the universal certificate for this URL?
The origin certificate expired on 1 February. Fix that then you can put the domain back on Cloudflare.
This should be set to “Full (strict)” or your users’ connections are not secured end-to-end. Ensure your origin SSL certificate is updated so it is valid.
I assume you have added (although not yet working) atb.bergamo.it to Cloudflare as bergamo.it is in the public suffix list. www would be a first-level subdomain of this so will be covered by the Universal SSL certificate wildcard.