If you watch that video, he sets the IP address to 192.168.4.1 then goes to the DHCP tab and the subnet has been changed automagically to 192.168.4.x. So the error you are seeing I’m guessing is because you tried to set the IP range in DHCP server different from the router’s IP subnet. Do it in the right order and set 192.168.1.1. Then set your Vero to use DHCP.
Now you have to make sure your NAS is on 192.168.1.235 again by giving it a fixed IP OR making your router always assign it that address.
Option 1: on the NAS turn off DHCP and set IP 192.168.1.235, subnet mask 255.255.255.0, gateway 192.168.1.1.
Option 2: On the router DHCP Server tab, use address reservation to link the NAS MAC address to 192.168.1.235. The MAC address should show up somewhere in the router’s list of connected devices.