I'm working on vROps 6.7, i'm getting the alert "NTP Servers are not reachable." very frequently like 25 times a day. There is a kb article for the same i.e. 2144694 which says to restart the casa service of vROps. I did the same but the issue is not resolved. Kindly suggest.
Check if they are reachable with traceroute and ping.
To check the NTP server date & time you can use w32tm. Open a command prompt and run:
w32tm /stripchart /computer:IPorHostname /dataonly /samples:5