Insufficient configured resources to satisfy the desired vSphere HA failover level on the cluster

Problem

Setting up a simple vSphere 6.5  environment, using percentage-based HA we have been seeing the following Configuration Issue flag on the cluster .

Insufficient configured resources to satisfy the desired vSphere HA failover level on the cluster …

You can see the alarms have Acknowledge/Reset options, this is a Configuration Issue message instead.

I have tried below steps to resolved this:

• Turn on, or turn off Proactive HA and then disable HA on the cluster, then re-enable HA
• Verify no firewall is interfering with HA
• Use various methods to reset FDM on the hosts – disconnect/reconnect, move into another cluster, so on…
• Set AC percentage to a different, low value (10% CPU/Memory)

In our case  above options not worked  , below is the configuration we tried  , and 25 % is what we given manually and this throws a configuration issue:

That worked, as a workaround.  Unfortunately, setting a value (1%, 10%, 25% ) for percentage based AC causes the config issue.  When I disable Override, the calculated value is 33%  by automatic .  So, it has nothing to do with manually specifying a value, rather than the particular value specified. Once it is calculated value itself and the issue got resolved .