On the host that is timing out, can you look in /var/log/fdm.log and /var/log/hostd.log
You can also try and right-click the host and select "Reconfigure for vSphere HA"
I've tried the individual reconfigure and that fails too. out of 12 hosts one has been elected master 2 are initializing and it says 9 are unreachable.
I'll take a look at the logs.
Correction, it is saying 9 are initializing and 2 are unreachable.
I'll take a look at the logs on the hosts that is says are unreachable.
If nothing helps... go to the cluster and disable HA in total, activate it again and in all my cases with the timeout error this helps. Most important is that all settings are restored. This is a different behaviour compared to the earlier years.
Do check with your network guy if any changes have been performed on network switch(es) where these ESXi hosts are connected to. It is possible hosts are not able to communicate with each other due to which HA seems to have gone crazy.