ntopng not accessible after upgrade

I've had ntopng working for a long time, but it's not working for me after an upgrade today. I ran:
sudo apt-get upgrade
sudo apt-get update
After these completed, I now get no response in my browser: http://192.168.0.222:3050/

sudo /etc/init.d/ nprobe status
returns "nprobe running" and
sudo /etc/init.d/ntopng status
returns " ntopng running as 3361"

What can I do to check why it's no longer working?