After setting up my main Deco and connecting to my modem with dynamics IP, the Deco obtains a WAN IP address, gateway and DNS addresses succesfuly. However, the subnet mask is always empty. In this situation, none of my connected devices are able to browse and the Deco shows a solid red light.

As soon as I change to Static IP and enter a subnet mask (WAN) manually, it starts to browse and LED changes to green. I go back to Dynamic IP and it stops again.

Problem is that I cannot leave the config on Static IP as my ISP will always change IP of my modem and I also have not been able to figure out how to enter a subnet mask when dynamic IP is selected. Don't know why it always blank in dynamic IP either. Please help.