Please take a look at this:
In short since your site is on a subdomain it’s automatically protected due to a wildcard SSL certificate installed on the base domain. You don’t need to do anything, aside from enforcing HTTPS for visitors.
That being said, when I visit your site I have no issues, and the wildcard SSL certificate is working just fine.
For this reason it’s clear the errors you’re seeing are unrelated to your SSL certificate. Like the error from Firefox says, it could be because your network administrator, ISP, or antivirus software/firewall is interrupting the connection. Either way, it isn’t something on the server’s end. The changes to SSL are a coincidence.