Reported in https://github.com/chrissimpkins/Hack/issues/24
Turn your firewall on, then attempt to install the font again.
Reported in https://github.com/chrissimpkins/Hack/issues/26
This is a known issue with the Java renderer in these editors and not an issue with the font. This has been reported on the JetBrains issue tracker. Updates will be posted to the above issue report.