@LRashley Have you put the router in the AT&T box in passthrough mode?

If not, search for 

AT&T Fiber - Own Router - David Puplava

He does a really good step-by-step tutorial.

  @BradLouKy amazing! Thanks. I had already setup as a pass through and turned off the WiFi at the router.

i, however, had not changed the subnet. And I was using the blue and not the yellow port with what is clearly not a 7 cable.

i made the changes as recommended. We shall see if that helps.

if anyone else has suggestions, I am open. Thanks again Brad.

  @LRashley Using the Deco app go to -> More -> Network Optimization and -> Scan.  If it finds interference it will provide the option/button to "Optimize".  Please update us if it finds interference...

  @jzchen I did the scan in multiple places in the house and never found anything. But since making the changes mentioned in the previous posts, we haven't had a drop. So fingers crossed it stays that way. Thanks for the suggestions!