Hi
Arent you able to ping the PCs connected on the other side ??
Can you post the config of both the routers ? also the show ip route o/p here ?
The best thing here would be using a /30 subnet mask for the Serial connectivity between the Links connecting the router instead of /24.
In normal working live production environment u cant afford to loose a /24 for just configuring the WAN interfce since u will use 2 ips here and the other remaining ips will be wasted cant be used anywhere else.
so better to try out with general recommendations and best practices.
regds