The Nanoleaf Aurora only supports 2.4GHz networks at this time.
5GHz networks are often broadcast by WiFi 802.11n/ac compatible routers, while 2.4GHz networks are required for compatibility with earlier WiFi versions (a/b/g). The biggest advantage to 5GHz is speed, but it comes at the cost of range, which is very important for the Aurora to work well.
If you are having trouble connecting to your local network, make sure your router is configured with 2.4GHz enabled. Most routers connect the 2.4GHz and 5GHz networks internally so all devices can talk to each other.