Edit: have now discovered that there was a mismatch between the root installation of VB and the user versions of the extension pack - I don't think I've ever seen this before. It would appear therefore, to be a slight difference in where the extension pack info is picked up from .. certainly the version under the user installation was well out of date(!), so I don't think this is a RB issue but rather something that's changed between VB 7.1 and 7.2.
Extension Pack not detected
Website certificate expired - can connect via Edge, but Firebox refuses.
I've been having the same problem with a new server build (Ubuntu 22.04). Turns out the fix is to issue service vboxweb-service restart once the server is up and running. For some reason it won't listen on the port until it's restarted.
As it turns out, that's not strictly true. I've just moved a number of VMs that were...