oa@du:~$ gpg --keyserver keyserver.linux.it --recv-keys  D63913EF50D0AE60
gpg: requesting key 50D0AE60 from hkp server keyserver.linux.it
?: keyserver.linux.it: Network is unreachable
gpgkeys: HTTP fetch error 7: couldn't connect: Network is unreachable
gpg: no valid OpenPGP data found.
gpg: Total number processed: 0
du:/home/oa# gpg --armor --export  D63913EF50D0AE60 | apt-key add -
gpg: WARNING: nothing exported
gpg: no valid OpenPGP data found.