Try this:
Make a backup of /etc/resolv.conf and remove any file write protection (if enabled):
sudo cp /etc/resolv.conf /etc/resolv.conf.bak && sudo chattr -i /etc/resolv.conf
Then, run the following command to auto-generate an /etc/resolv.conf file with Google as the DNS servers:
echo -e "nameserver 8.8.8.8\nsearch 8.8.4.4" | sudo tee /etc/resolv.conf
If desired, once you have completed the edits you can write protect the new resolv.conf (optional).
To write protect /etc/resolv.conf
issue the following command::
sudo chattr +i /etc/resolv.conf
To remove write protection from /etc/resolv.conf
issue the following command::
sudo chattr -i /etc/resolv.conf
To restore /etc/resolv.conf to its original state issue the following command:
sudo chattr -i /etc/resolv.conf; sudo cp /etc/resolv.conf.bak /etc/resolv.conf
You could alternately test the cloudflare dns servers:
Run the following command to auto-generate an /etc/resolv.conf file with cloudflare as the DNS servers:
echo -e "nameserver 1.1.1.1\nsearch 1.0.0.1" | sudo tee /etc/resolv.conf
Reboot after updating your nameservers.