ESXi host shows "vSphere HA agent on host cannot reach some management network addresses of other hosts"

Products

• VMware vSphere ESXi

Issue/Introduction

• ESXi host alert : vSphere HA agent on host cannot reach some management network addresses of other hosts
  
  
  
• vSphere HA Agent report Error : Cannot Reach Management Network Addresses. 
  
  
• We see below error in affected host's fdm log present at /var/run/log
  
  YYYY-MM-DDT07:14:36.617Z In(166) Fdm[3508814]: [Originator@6876 sub=Monitor opID=pingableAddressMonitor. cpp: 115-55318fe8]No ping reply from OtherHostIP
YYYY-MM-DDT07:14:36.6172 Db (167) [Originator@687sub=FDM opID=WorkQueue-3a450341] New event: EventEx=com.vmware.vc.HA.NotAllHostAddrsPingable vm=host=host-30##### tag=host-30##### : 1285265540:2
  
  
• Ping test will fail between the ESXi hosts on management IP

Environment

vSphere 8.x

VCF 9.0

Cause

This issue occurs when a host experiencing a vSphere HA event is unable to ping or reach the Management Network IP address of other hosts in the cluster. The cause could be firewall rules, an incorrect Management Network IP, use of IPv6, or other network connectivity issues.

Resolution

There should be bidirectional communication between ESXi hosts on 8182 TCP and UDP

Check with internal network team and ensure the ping works between the affected hosts.