You should be able to regenerate it by running this command:
sudo resolvconf -u But perhaps the permissions on the file resolv.conf itself are screwy. So just blow away that file like this:
sudo rm -f /etc/resolv.conf Then run sudo resolvconf -u again.
And if somehow this doesn’t work, run this dpkg-reconfigure command:
sudo dpkg-reconfigure resolvconf Just punch through the prompts, reboot the machine and see what happens.