Ubuntu nightly PPA installation Key error


I tried installing the Ubuntu PPA mentioned in the official website, but fails with the following error:

gpg: keybox '/tmp/tmp0oxr4if6/pubring.gpg' created
gpg: keyserver receive failed: No keyserver available
Failed to add key.

Do any one know where to get the key and manually add it?

Did you follow the instructions on the Linux download page?