Below are explanations of what causes this issue and how to resolve it...
This condition can be caused by a few possibilities. If the WiFi indicator in the header of each page is entirely gray in color, it means there is no internet connection. If network credentials have been previously entered, please restart the controller to re-initialize the connection.
If no networks appear under Menu>Settings>Network>Wireless, ensure the WiFi Dongle is fully inserted into the USB Port/Cable (if applicable) or inspect the WiFi antenna (if applicable).
Otherwise, if the problem persists, please contact SDS Industries for further troubleshooting assistance.