I use VirtualBox quite a bit. It is how I do things like check my answers, look for bugs, test new OSes, and general things like that.
Well, on my Lubuntu 18.04.5, it had stopped working with my kernel. The kernel had updated from the older (4.8.x maybe?) and is now at 5.04.x and VB wasn’t working. This needed to be resolved.
Crack open a terminal and try this:
And Bob’s Your Uncle.