Can't find Security->Settings. Want to modify DoS settings.

All I want to do with the setup is for the device to answer a ping and allow configuration access from a central point

I have 2 older tp-Link routers in the network, and they answer just fine.

Their addresses are:

192.168.0.1   // This router connects to the ISP modem

192.168.1.1  // Linked to 192.168.0.1

The AX21 is also linked to 192.168.0.1

It's configured in 'Wireless Router Mode'

Other than the above problems, it works just fine.

The current prom OS is 4.2

I've done a total reset, and tried reconfiguring it several times.

What am I doing wrong?