ARRIS Touchstone Gateway not being "seen" by smartphone/tablet/ or computer

I can connect to the Cox network without any issues, but, if I attempt to manage my connection via the Cox website (PC) or via the Cox app on my iPhone or iPad, I am unable to see my connection.  I.E., I cannot "see" what devices are connected, nor can I see my settings.  Via the Cox app, I get a message "Installed Modem: No Modem Found"

I had a Cox technician out today and he swapped out the router.  He tested the connection and said that I have a good connection.  Nevertheless, I am unable to manage my settings or view what devices are connected to my account.

Anyone have any ideas what might be going on?  Any and all thoughts greatly appreciated.