This thread is now archived and closed to new comments. Some of the links and information provided in this thread may no longer be available or relevant. If you have a question please post a new topic.
You could disable band steering in the modem's 2.4 GHz WiFi settings this will result in 5 GHz WiFi band having 5G added to the end of the normal SSID. If you cannot see the normal SSID then 2.4 GHz WiFi radio is not transmitting.
If 2.4 GHz WiFi is working you moght find that devices that did not connect now connect. Some older device can't connect when the 5 GHz and 2.4 GHz WiFi bands have the same SSID.