There is little point to having an email server with only one address on it. Most of them have thousands. There is no way of knowing what accounts were on clintonemail.com without access to the server.
I’ll bet she’s been using one of those emails to troll here!! There have been lots of attacks on Scott Walker that sound liker her.
If your objective is to avoid having communications archived and subject to subpoena, it does little good if the other persons you communicate with is on a .gov address, because HIS copy of the email will be archived. To be secure, ALL parties to the communication must be on private servers.
Tracking this down would lead to interesting data.