Explanation/Reference:
Explanation:
First we should verify if the ports connected between R1 and R2 is in "up/up" state with the "show ip interface brief" command on R1 & R2.

Note: We learn R1 & R2 connect to each other via E0/2 interface because the IP addresses of these interfaces belong to 192.168.10.0/30 subnet. Both of them are "up/up" so the link connecting between R1
& R2 is good.
Next we need to verify the ntp configuration on R2 with the "show running-config" command:

So there is only one command related to NTP configuration on R2 so we need to check if the IP address of
192.168.100.1 is correct or not. But from the "show ip interface brief" command on R1 we don't see this IP
-> This IP address is not correct. It should be 192.168.10.1 (IP address of interface E0/2 of R1), not
192.168.100.1.