If you share the make and model of your WiFi router or WiFi access point, I would be more than happy to try and walk you through setting up a 2.4GHz SSID as it sounds like right now your router/access point is only broadcasting a 5GHz SSID.
I’m not trying to pour salt on any wounds or make any excuses here. With that said, 2.4GHz WiFi is what most Internet of Things communicate on. Is 2.4GHz older, yes it is. However, older doesn’t mean crummy or worse in all cases. The fact is 2.4GHz WiFi penetrates through walls better and travels much further than 5GHz from any given router.
You can test this yourself if you would like. Purchase the newest most expensive wireless router or access point that you can afford. Setup both a 2.4GHz SSID and a separate 5GHz SSID. Go for a walk down the block with your mobile device then start walking back towards your home while monitoring the wireless signals that come into view on your mobile device. The 2.4GHz SSID will be detected by your mobile device long before the 5GHz.