This error will occur if Safari cannot find the Highfive application on your Mac.
- Go here to download the Highfive application installer: https://start.highfive.com/install/mac
- Open Highfive Installer.dmg from your Downloads.
- Double-click the Highfive Installer icon.
- Click Open.
- Click Update.
- Navigate to any Highfive meeting link or go to start.highfive.com in Safari. The Highfive application will launch properly now.
Still seeing this error? Please report the issue to Highfive Support at firstname.lastname@example.org.