The error was encountered during cluster verification utility for Oracle Grid Infrastructure for RAC installation. The error can be reproduced using either of the following commands:

./runcluvfy.sh stage -pre crsinst -n ol7-rac1,ol7-rac2 -fixup -verbose

OR

./runcluvfy.sh comp clocksync

Now, run below command to verify NTP peers.

ntpq -pn

Next, validate that you have atleast one external server configured in /etc/ntp.conf file. I have these in the file.

server 0.rhel.pool.ntp.org iburst
server 1.rhel.pool.ntp.org iburst
server 2.rhel.pool.ntp.org iburst
server 3.rhel.pool.ntp.org iburst

Everything looked good. Then i figured out that it was issue with my internet connect on the server. I allowed the internet and it started working.