Hi!
This is just a FYI post, since I’m not sure who I should contact about this issue. Blizzard support channels seem to be more about game related issues.
The certificate for diablo2 . blizzard . com (cannot include direct links in this post) has not been configured correctly and it’s resulting in a security exception when using any of the popular internet browsers out there.
DigiCert diagnostic tool is saying that the certificate is still valid, but that the server is not sending the required intermediate certificate.