Hello,
1.The IP address of your WAN interface is incorrect, using the subnet mask 255.255.255.0, the address can range from 192.168.1.1 to 192.168.1.254.
2. 2.When changing the IP address of the router WAN interface, use the same address for the gateway of your computer.
For example:
RUT240 wan Interface : ip - 192.168.1.254, mask 255.255.255.0, gw 0.0.0.0
pc interface : ip 192.168.1.200, mask 255.255.255.0, gw 192.168.1.254
Best regards.