Roku Express, Smart Lights, and other 2.4ghz Devices Not Connecting/Cannot Find WiFi

Yesterday (Sunday, October 15th) around 4:30PM EST, my Roku Express, Amazon Smart Lights, and a few other 2.4ghz band devices lost access to WiFi and have not been able to reconnect. In fact, the Roku Express can no longer find my SSID. 

I've tried factory resetting the Roku, resetting the router via the Xfi App, and performing a hard reset on the gateway itself and I am still unable to connect. I can't adjust the gateway settings because they are being automatically controlled for an "optimal experience". 

I need help to get my WiFi straightened out. My home runs off of smart devices like lights and security cameras and right now, we're quite literally in the dark.