Most likely the symbolic link /etc/resolv.conf -> ../run/resolvconf/resolv.conf is missing on your system. To restore it, do the following in a terminal.
sudo apt-get install resolvconf
sudo dpkg-reconfigure resolvconf
If you want to use 18.104.22.168 as your nameserver then set up either ifup or NetworkManager to use that nameserver address for the interface(s) that it brings up.
If you use ifup then edit /etc/network/interfaces and, in the stanza for the interface in question, add the line "dns-nameservers 22.214.171.124"; then ifdown the interface and ifup it again.
If you use NetworkManager then open the connection editor and add 126.96.36.199 as an additional nameserver address (network indicator | Edit Connections... | Wireless | myconnection | Edit... | IPv4 Settings | Additional DNS servers).