The lights on the modem indicate the status of your connection. For any connection issue, the lights on the modem is a good place to start from.
Here is a description of what they mean and where to locate them depending on your modem.
The Wi-Fi Halo has two LED lights which indicate the status of your broadband service and Wi-Fi connectivity
The Wi-Fi and WPS buttons are located on the side of your Wi-Fi Halo.