Panoramic Wi-Fi - Loses connection a few times a day

My internet connection 

download: 558.3

upload:  37.1

ping 12  MS 

I'm pretty sure my modem is rebooting   I have a problem were my devices disconnect for a few minutes and its  happening a few times a day. 

My internet connection speed is pretty fast.

* I even went to the Cox store to replace my modem

* Split my 5 ghz and 2.ghz.

* I moved the modem to another section of the house.

Does anyone have any ideas of what I could try next ? 

Thanks Jason