ping: google.com: Temporary failure in name resolution

I've faced the exactly same problem but I've fixed it with another approache.

Using Ubuntu 18.04, first disable systemd-resolved service.

sudo systemctl disable systemd-resolved.service

Stop the service

sudo systemctl stop systemd-resolved.service

Then, remove the link to /run/systemd/resolve/stub-resolv.conf in /etc/resolv.conf

sudo rm /etc/resolv.conf

Add a manually created resolv.conf in /etc/

sudo vim /etc/resolv.conf

Add your prefered DNS server there

nameserver 208.67.222.222

I've tested this with success.

If you get the IP address from a DHCP server, you can also set the server to send a DNS server. Or add the nameserver 8.8.8.8 into /etc/resolvconf/resolv.conf.d/base file. The information in this file is included in the resolver configuration file even when no interfaces are configured.