You can set it in the DHCP table in the LAN option

If you think it's a DNS problem, why not set a static DNS server on the router to have a try? Go to web interface, LAN->Disable DHCP server, set 8.8.8.8(common google DNS server) for static DNS...

I think you can reset the modem and then try to reconfigure first, the modem has a reset button on itself.

Check if you have ticked Connect on demand. That option means the Internet will drop when you don't search the Internet for several minutes. You may find the option in Interface Setup-> Internet....

wireless network names had better be different so that you can choose which to connect. 5GHz is much more faster than 2.4, if your device can detect the 5G signal, just choose that one. However, most...

So I think the most easiest way to do that is 1.Disable the DHCP server on 8970 2.Connect the LAN port(yello) of 8970 to your fiber modem And you can use 8970 both wirelessly and wiredly. Jibeji...