Error: vSphere HA agent on host cannot reach some management network addresses of other hosts

Products

• VMware vCenter Server

Issue/Introduction

• After modifying, creating, or deleting a management network on an ESXi host, the following error message is frequently logged in the vSphere Client:
  
  Error: vSphere HA agent on host cannot reach some management network addresses of other hosts
• The vSphere HA agent (FDM) continues to attempt access to the management network interface that was previously removed or reconfigured.

Environment

VMware vCenter Server 7.x
VMware vCenter Server 8.x

Cause

This issue occurs because the Fault Domain Manager (FDM) agent retains stale network metadata. When a management VMkernel interface is deleted or retagged, the HA agent may not automatically update its list of heartbeat addresses, leading to reachability alarms.

Resolution

To resolve this issue, reconfigure vSphere HA on the cluster to refresh the network metadata. Disabling and re-enabling vSphere HA does not impact the operation of running virtual machines.

1. Log in to the vSphere Client.
2. Select the affected Cluster in the inventory.
3. Navigate to the Configure tab.
4. Under Services, select vSphere Availability.
5. Click Edit and toggle the vSphere HA switch to Off.
6. Wait for the task to complete across all hosts.
7. Toggle the vSphere HA switch back to On.
8. Verify that the reachability alarms are cleared.

For detailed steps, see Disabling and enabling VMware vSphere High Availability (vSphere HA)