Error SSL - Actalis certificate

since yesterday afternoon, without having done anything, my site returns the attached error. in the cloudflare panel it was configured with SSL COMPLETE and in my web server there was a valid certificate issued by ACTALIS. if I set SSL FLEXIBLE everything works.Istantanea_2021-04-08_07-48-47

No NOT change your SSL to flexible it’s basically blurting out your data on an unencrypted connection, you should change it to Full or Full (strict), also try making a cloudflare certificate to see if that will fix the issue. P.S: What’s the link?