Dictation might not work if your Mac is connected to a network that uses a firewall, proxy server, or Internet filtering software that blocks access to websites. Ask your network administrator to make sure the following addresses are accessible:
|https://guzzoni.apple.com||TCP port 443|
If you want to use Dictation when you're offline, enable Enhanced Dictation in the Dictation & Speech pane of System Preferences while you are still connected to the Internet. After Enhanced Dictation finishes setting up, you can use Dictation features without an Internet connection.