@Andrea Ferrari We apologize for the frustration that you encountered while trying to setup SSL for your custom domain.
We took a look and it appears sitename.com is passing the test on sslshopper now.
Unless you made additional changes after your post, DNS propagation can take awhile (over an hour in rare cases). It's likely you encountered a DNS propagation delay.
If you have any further questions or concerns on this matter, please let us know.