The most likely reason for not seeing satellites is a poor view of the sky. Test with the GPS outside, with nothing overhead. The GPS is not designed to work indoors. Allow up to 10 minutes to capture satellites on the first use. It will be faster on subsequent uses.
If you are using the Vernier GPS Sensor on a computer, move it away from the computer by using the USB extension cable (included). Interference from the computer can hinder the satellite reception.
For additional information, see Vernier GPS Troubleshooting and FAQs