CM400

So I’m running the CM400 modem with the Nighthawk R7000 router. My Ethernet light on my modem is continuously blinking green. I’ve checked the Ethernet cord from router to my laptop, I’ve also connected my modem to my router and to my laptop. Everything works fine, until I try to connect to WiFi. It won’t let me connect or it won’t find my router. Need some help, my WiFi was working a couple hours ago. This just happened all of a sudden.