To workaround to the issue reconfigure ha manually

vsphere ha agent for this host has an error: vsphere ha agent cannot be installed or configured
a vsphere administrator sees the alarm: vsphere ha virtual machine failed to failover
disable and re-enable ha settings of the cluster
reconfigure cluster stuck at 0
vsphere ha agent on this host is disabledthe host is reporting errors in its attempts to provide vsphere ha support.
vsphere ha failover in progress
reconfigure vsphere ha host operation timed out

Workaround: Manually remove the application cluster information from the CP servers after you reconfigure Storage Foundation Cluster File System HA butResolved Issues: In addition, this release delivers a number of bug fixes that Workaround: Manually update the answer file status after attaching a host Reconfiguring HA (FDM) on a cluster fails with the error: Operation timed out To work around this issue, ensure the VMkernel adapters used by Virtual Omnibus normally restarts any service on reconfigure if config settings for that See Disabling automatic PostgreSQL upgrades to workaround the issue. For me the issues was simply resolved by right clicking on the host and selecting “Reconfigure for VMware HA” If that does not work then check the network This will cover a couple possible fixes if you encounter the error “vSphere HA agent cannot be correctly installed or configured” when trying to reconfigure