HDP 2.3, Ambari 2.1.2 All hosts show heartbeat lost

[#1]

Hi, I have 11 hosts and all of them are showing heartbeat lost and the icons are Yellow. I restarted the ambari-server and agents on all the hosts but the hosts are still in this state. Any idea what is going on.

[#2]

@jss Thank you for the responses. I have been able to resolve the issue