My UNA site was once hacked, no fault of UNA but rather the fault of other out-dated scripts on my other sites.

I would do a scan of all your sites according to files *with recent changes* and see if there is anything suspicious in the code. Malicious code is even attached to images and pdf files, too.

Hackers have automated tools now that do all the work. If there are vulnerabilities on your other sites, they can be exploited in a matter of seconds. Especially look out for Wordpress and the associated add-ons.

Hackers desire to use your server space and processing power - not disable your sites. In most cases. Still it does happen. And it is frustrating, as we can testify.

Check your error logs, too. And see if there is any server support that can take a look at things. That is, unless you are hosting the dedicated server yourself.

Let us know how it goes. And what you learn.