Ubuntu (I dont exactly know on which version its started to do so ) overwrites manual changes made to resolv.conf. Here is what you can
sudo vi /etc/resolvconf/resolv.conf.d/tail
Enter the below nameservers:
nameserver 10.34.34.221
nameserver 10.34.34.222
nameserver 10.34.34.222
and run
resolvconf -u
Done.