I too have experienced this issue multiple times since starting my service with Heliohost.
This normally happens during the week, very rarely on the weekends. And normally, once it starts happening, all of the Cpanel functions have a habit of ceasing to work. File Manager stops allowing uploads and no longer displays the files properly, PHPMyAdmin starts running sluggishly, or stops loading all together as well, and I can no longer access Horde to view email.
This will normally go on for about 2 hours or so, then either resolve itself, or end with the heliohost server no longer allowing access to my website giving the "Account Queued" message when the home page or any other index attempts to display, and showing a very stylish 404 page if any particular web page is attempted to be accessed.