Can't reach key server - are you behind a (company) firewall?
If you can't reach any key server, chances are you are behind a firewall.
To work around this
- open GPG Keychain
- from the top menu select GPG Keychain > Preferences...
(⌘ , Keyboard Shortcut)
- Key server tab
hkps://hkps.pool.sks-keyservers.net:443into the address field
- press Enter to confirm
If that doesn't work, try the less secure
If you are good friends with the IT department, ask them to open up port 11371 TCP and save your colleagues some trouble.