Why did Branch1 router lose WAN connectivity with R1 router?
A. interfaces.
B. The PPP multilink group is misconfigured on the R1 serial interfaces.
C. The Branch1 serial interfaces are placed in a shutdown condition.
D. The IP address is misconfigured on PPP multilink interface on the Branch1 router.
Answer:D
Why did Branch1 router lose WAN connectivity with R1 router?
A. interfaces. B. The PPP multilink group is misconfigured on the R1 serial interfaces. C. The Branch1 serial interfaces are placed in a shutdown condition. D. The IP address is misconfigured on PPP multilink interface on the Branch1 router.
Explanation: First we should check both routers with the "show ip interface brief" command. On R1: