It can be a connection issue so we always recommend rebooting your superhub and Virgin box by the mains, allow the hub to load back up first before turning on the box so it can then connect to your home network.
As Josh_RW has mentioned please keep an eye on it for us and let us know if there's any problems.
It's happened a few times and I'm beginning to think it's related to when the hub has been off for any reason. It's as if it doesn't synchronise properly for a few days afterwards. I'll post back if I figure it out.