2.4ghz not showing up in networks, cannot use my home security app

Before Sunday I could use my home security app, it stopped Monday morning 2/16.
I tried resetting my security DVR, tried resetting the Xfinity gateway.
I keep getting a "cannot connect, check network connection" from the security app.
Today I noticed the 2.4ghz is no longer shown.
I tried to go into the app as AI suggested and split the bands but the app will not allow me to do so.

Do I have to go buy a router so I can use my $500 security system that worked fine until the other day when my 2.4 network seems to have vanished?