Did NOT work with Ubuntu 20.04 installation
There's a setting with Cisco AnyConnect to "Allow local (LAN) access when using VPN (if configured)
Refer: https://www.lullabot.com/articles/fixing-docker-and-vpn-ip-address-conflicts (pdf)
By default Cisco AnyConnect was interfering with Docker running on localhost. The fix was to have Docker use a different range of IP addresses.
$ sudo nano /etc/docker/daemon.json
And the restart your computer.