If you VNC into your server after a failed restart and you see this error, don't panic. This issue happens from time to time with Virtualizor. Below are the steps to rectify the issue:
1) Please login to the user Virtualizor panel here. Optionally, you can just manage the VPS inside of your client area and skip to step 3.
2) Once you've logged in, click the arrow on the far right of the VPS having the issue.
3) From here, you should see a screen similar to the following. Click the "Settings" button, as outlined in the picture:
4) Once you've navigated to this page, please click "VPS Configuration".
5) Tick both "ACPI" and "APIC" (they should have a blue checkmark next to them after completing this).
6) You should be met with a return: "The settings have been save successfully". You may now restart the VPS and attempt to reconnect again. If this does NOT work, go ahead and open a ticket HERE