A network administrator configures a router with the following IP address information:
Gigabit Ethernet 1 Interface: 10.10.0.1/24
Serial 0 Interface: 10.10.0.253/30
Clients are connected to a switch on the gigabit Ethernet interface; the ISP is connected to the Serial 0 interface. When the router configuration is complete and client devices are reconfigured, all clients report that they are unable to connect to the Internet. Which of the following is the MOST likely reason?