Keep losing internet connection

[Ewillhelm]

So my 27000P is behind an AT&T router. Every couple days, the internet connection is gone, and the only way to get it back is a restart. This is annoying as the kids are all doing school online, and they all come running to me freaking out that they lost the connection. At first I thought setting static IP addresses might fix it, as I noticed this often happens when I turn on another device after everyone else is on. But a tech savvy friend of mine says that shouldn't be necessary. "I have 4 computers, 2 Alexas, 4 phones etc all going day in and day out and I never had to do that." 

I am currently in Router mode. Would I be better of in AP mode? I read the descriptions of both, and at the time Router sounded like it made more sense, but I could be wrong. 

I also have the QoS thing going. Is that actually a detrimental thing? I can easily imagine folks saying, "Oh heck no, turn that off. It's a nightmare." So worth a check, I guess.

Anyone have any helpful input here?

Thanks!

Oh, and I also notice the firmware update check never detects new firmware. It'll say no new updates available, but then if I Google it, there IS a new one, so I've been doing manual firmware updates. I am currently on 1.3.2.126_10.1.66

[plemans]

What att router are you using? 

Is it in passthrough/modem only mode? 

Or the netgears IP address entered into the ATT devices dmz? 

Or you could try the netgear in access point mode. 

otherwise your running a double nat. It might be causing your issue. 

https://kb.netgear.com/30186/What-is-Double-NAT

[Ewillhelm]

Router is a BGW210 

It is in passthru mode. Its firewall settings are thus...

Packet Filter: On

IP Passthru: On

NAT default server: Off

Firewall advanced: On

That said, I don't think it's doing any of the dmz stuff.

[plemans]

have you tried it with the att router in router mode and the netgear in access point mode?
that model of att router isn't known for the greatest passthrough mode.