FleetKraft could not be reached from this device: the Wi-Fi or mobile data dropped, or a VPN or firewall is blocking it. A red bar at the top says when the browser is offline. What was already on screen stays there, and FleetKraft loads again by itself as soon as you are back online.
"FleetKraft is busy for a moment" means an update is being installed: wait a few seconds and try again. If other websites open but FleetKraft does not, contact support.