Nighthawk AC1900 C7100V loses internet connection every other week

Just bought this modem/router combo about a month and a half ago and about every other week I lose internet connection. I have to unplug power to the device and let it re-connect. After I do this the net is back up and running for another week or 2... Why does this keep happening? I have ADT and a Hikvision security camera system that I need to be able to access remotely, so this can be a pain. I've read some other threads on this but not clear answers that I have found. Can anyone help me out? Thanks.