already tried that. I rebooted the host and everything is back up now. thanks
I believe you are facing similar issue explained in the below link.
http://www.virtually-limitless.com/nsx/nsx-6-2-communication-channel-health-check/
It looks like your Firewall agent is down. Check the status of it & restart it if it is down.
/etc/init.d/vShield-Stateful-Firewall status
already tried that. I rebooted the host and everything is back up now. thanks