Server down. Admin, but not Domain Owner

I woke up this morning to a flood of emails alerting me that my site’s “Server Not Found.” I’m the primary admin for the site, but not the owner. To add a twist, the owner has been MIA for a few months and not reachable by email or FB.

What can I do to get the site back up? I apologize if this is a n00b question.

I suggest you to open a support ticket immediately: