Your device is connected wirelessly to the hotspot but there is no internet connection.
Ensure the hotspot recognizes your device as being connected. Located on the bottom right of the screen is a "U" symbol with a number. For each device connected, the number should increase.
Power cycle the hotspot:
Ensure the hotspot is unplugged from power.
Hold the power button for 30 seconds, there should be nothing on the screen.
Release the power button.
Hold the power button down until "Welcome" is displayed on the screen.
Reconnect to the hotspot.
Power off your computer/device and power it back on.
An error has occured with the hotspot or computing device and it needed to be restarted.