keyserver receive failed (on every keyserver available)

I recently installed Ubuntu 17.04 and I'm not able to add any ppa.
I tried to manually add keys using different keyservers but on every attempt I'm getting keyserver received error: $ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0F164EEB Error Received: Executing: /tmp/apt-key-gpghome.qm2WNA0lTK/gpg.1.sh --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0F164EEB gpg: keyserver receive failed: No keyserver available $ sudo apt-key adv --keyserver keys.gnupg.net --recv-keys 0F164EEB Error Received: Executing: /tmp/apt-key-gpghome.O681PzEx7r/gpg.1.sh --keyserver keys.gnupg.net --recv-keys 0F164EEB gpg: keyserver receive failed: Connection refused It is the same case with other keys. I'm not able to add any PPA.