NSX - Enable and Disable Firewall are greyed out

Issue
Today I face out with a singular issue, whole clusters show me Communication Channels DOWN and Firewall status ERROR.

Checking inside ACTIONS in Host Preparation tab I saw that Resolve, Enable and Disable Firewall was greyed out as well even if EAM was UP and running Normal.

Looking inside logs, I haven't found something interesting ... NSX Controllers were UP and Running Normal, NSX Cluster was UP, communication between various components of the NSX environment has been tested successfully with the ping ... so, everything seemed to work properly.

I tried to create new objects (examples Logical Switches) and was created and synced correctly on every hosts.

Then alternatively I tried to reboot both NSX Manager and vCenter ... without success. Communication channel were still DOWN and Firewall status still in ERROR.

I also tried to restart the on Control Plane Agent (netcpad service) on some hosts, randomly chosen, but without success .... communication between NSX's objects works fine but at GUI level I continue to see the error.

Solution
The fastest way I found to resolve the issue was to put into maintenance mode the ESXi host and then, one by one, reboot every single host of the whole cluster.
After the reboot of the ESXi host, the Communication channel and the Firewall status was properly recognized.

After all hosts have been restarted, the grayed out option in ACTIONS became available.

That's it.