Comment 4 for bug 1818629

The server itself should be fine, it is possible to receive loads of other keys from there, maybe they're just blocking pings.

The key for old versions listed at https://developers.hp.com/hp-linux-imaging-and-printing/hplipDigitalCertificate.html imports just fine

$ /usr/bin/gpg --keyserver pgp.mit.edu --recv-keys 0xA59047B9

but not the one for current versions

$ /usr/bin/gpg --keyserver pgp.mit.edu --recv-keys 0xA59047B9

so it seems there is something wrong with the key on the keyserver (for weeks at this point).