ESXi Host Enters Not Responding State

Products

• VMware vCenter Server

Issue/Introduction

An ESXi host enters a "Not Responding" state in vCenter Server, while virtual machines continue to run. Migrations via vMotion fail, and all management operations (including vDS reconfigurations or local CLI commands) hang or experience extreme latency. The vobd.log stops updating entirely during the hang, but prior entries indicate hardware and hostd communication failures:

An event (esx.problem.storage.iscsi.discovery.connect.error) could not be sent immediately to hostd; queueing for retry.

You might also see logs similar to the below in vpxa.log on vCenter server.

Failed migration referring to the impacted host.

9025572:2026-03-11T10:05:29.655-06:00 error vpxd[558931] [Originator@6876 sub=VmProv opID=m3oijgoq-5177871-auto-32z9s-h5:71051621-dd-01] Local-VC Host Migrate failed at vpx.vmprov.PrepareSource for poweredOn VM 'VMware Aria Operations for Logs' (<VM moid>, ds:///vmfs/volumes/<datastore-uuid>/VMware Aria Operations for Logs/VMware Aria Operations for Logs.vmx) on host-moid (<REDACTED_IPS>) in pool <resgroup_id> with ds ds:///vmfs/volumes/<datastore_uuid>/ to <host_moid> (<REDACTED_IPS>) in pool <resgroup_id> with ds ds:///vmfs/volumes/<datastore_uuid>/ with migId <uuid> with fault vim.fault.Timedout:  as Operation: Local-VC_NonDRS_ComputevMotion

Missed Heartbeats referring to the impacted host.
9025791:2026-03-11T10:05:35.813-06:00 info vpxd[06317] [Originator@6876 sub=InvtHostCnx opID=HeartbeatStartHandler-25e96e12] Missed heartbeats for host; [vim.HostSystem:<host-moid>,<REDACTED_HOSTNAMES>], missed: 170, msg: {srv: 1528238, gen: 234054, ct: 303183, bld: 24280767, cnx: <uuid>, ip: <REDACTED_IPS>}
9026623:2026-03-11T10:07:35.841-06:00 info vpxd[06317] [Originator@6876 sub=InvtHostCnx opID=HeartbeatStartHandler-25e96e12] Missed heartbeats for host; [vim.HostSystem:<host-moid>,<REDACTED_HOSTNAMES>], missed: 2, msg: {srv: 1528238, gen: 234056, ct: 303195, bld: 24280767, cnx: <uuid>, ip: <REDACTED_IPS>}

Other tasks may be failing or constantly running such as vSphere Distributed Switch operations.

"Cannot complete a vSphere Distributed Switch operation for one or more host members."

Environment

VMware ESXi 8.0.3

Cause

Possible hardware issue on the ESXi host which paralyzes management agents (hostd) and logging services.

Resolution

1. Perform a physical hard reboot of the affected ESXi host to clear the memory and kernel lockup, allowing it to reconnect to vCenter Server.
2. Engage the hardware vendor to run a full hardware diagnostic suite. (e.g., Dell ePSA, HPE Insight, or Lenovo XClarity).
3. Review the hardware management console (iDRAC/iLO/BMC) for recorded ECC or Multi-bit memory errors and replace failing components as recommended by the vendor.