Astute Devices can only work on 2.4GHz networks. Many newer routers have a dual output frequency of 2.4 GHz and 5 GHz. If possible switch off the 5G transmission. Alternatively, ensure that your mobile device is on the 2.4 GHz frequency and then pair the Astute device on the same 2.4 Ghz frequency.
More information: Astute Range