S33: Front Panel LED is solid Amber for 20s and then flashes white (and repeats)

I came home from being out for a couple of days and my Arris S33 modem appeared in an error state. No internet connection on any of my devices. The front LED turns a solid amber for 20 seconds, then flashes white, then turns off for 2 seconds before repeating that cycle. Tried hard resets and checking cables; also tried troubleshooting with Cox, but the modem just remains in whatever state it’s in. Modem is not responding to input from the reset button, either. 
 

I’m not sure what to do as I haven’t seen any posts with a similar issue to this. I received the modem as a hand-me-down and have only had it plugged in for less than a month (and it’s worked fine until now).