Something in the shutdown triggers a start of a service or doesn't stop in time. Since something is still running the shutdown never completes. Looking at the screenshot for instance it says "Stopping monitoring of LVM2 mirrors, snapshots etc. using dmeventd or progress polling...". But there is no acknowledgment [OK] that it has completed. I'd start looking there.

@aaronstuder said in Install Jitsi-Meet on Debian 9 minimal: @JaredBusch care to elaborate? It's working for me. No, because it has all been posted. between here and my other thread.