wifi not working

Ive had the same thing happen, It was working fine for about 11 months and then one day I was looking through my ring door bell and when I got home no wifi, it does not come up on my phone, laptop or ps4 wifi list, but I can plug into it and it appears fine just no Wifi. I've tried soft, hard and rebooting it and nothing. I've logged into the router and it says under the wifi drop down menu "No files found" and when I try to click on advance the router turns off on by itself. I've checked on netgear which was no help unless I give them money 90 days isn't much support in my opinion. SO, you need the important details here this is what I have Ac1200 wifi cable modem router  model c6220  firmware v1 02.02