HCX Bulk Migration Fails with Error "Initial Sync Failed : SSL handshake error: Remote host terminated the handshake"

Products

• VMware HCX

Issue/Introduction

• VMware HCX Bulk Migration fails during the initial synchronization phase.
• The following error is observed in the migration details: Initial Sync Failed : SSL handshake error: Remote host terminated the handshake
• The HCX Appliance Management UI (port 9443) shows the vCenter Server connectivity status frequently flapping between connected and disconnected states.
• The HCX app.log reports intermittent communication failures with the vCenter Server.
  
  2026-06-13 02:18:48.273 UTC [OnPremL2cStatsService_SvcThread-19, Enterprise: HybridityAdmin, Username: HybridityAdmin, TxId: ] ERROR c.v.v.h.a. vcenter. VcConnection- Error Logging onto VCenter:https://<vcenter-fqdn> User:#####, message: javax.net.ssl.SSLHandshakeException: Remote host terminated the handshake
2026-06-13 02:18:52.479 UTC [TopologyService SvcThread-43, Ent: HybridityAdmin, , TxId: #####-###-####-###-####123] INFO c.v.v.h. vsphere. UpdateInventoryJob- <vcenter-fqdn>: Time taken to persist 1000 unique updates: 11849 ms.
2026-06-13 02:18:52.479 UTC [TopologyService_SvcThread-43, Ent: HybridityAdmin, , TxId: #####-###-####-###-####123] INFO c.v.v.h. vsphere. UpdateInventoryJob- <vcenter-fqdn>: Time taken to process 1000 raw updates: 12488 ms (includes wait time as well, if any.). 

Environment

VMware HCX

Cause

The vCenter Server Envoy proxy exceeded its maximum connection limit of 2048, leading to HTTP connection exhaustion, dropped SSL connections, and terminated handshakes with the HCX Manager.

Log reference: /var/log/vmware/envoy/envoy.log

2026-06-13T18:39:17.368Z info envoy [57339] [Originator@6876 sub=connection] [Tags: "ConnectionId":"88311"] remote address : <HCX-Mgr-IP>: 41928, TLS_error: |26843
5588: SSL routines: OPENSSL_internal : CLIENTHELLO_TLSEXT | 268435646: SSL routines : OPENSSL_internal : PARSE_TLSEXT: TLS_error_end
2026-06-13T18: 39:22.917Z warning envoy [57346] [Originator@6876 sub=filter] [Tags: "ConnectionId":"88322"] remote https connections exceed max allowed: 2048
2026-06-13T18: 39:22.9172 warning envoy[57346] [Originator@6876 sub=filter] [Tags: "ConnectionId":"88322"] closing connection TCP< ##.###.##.##:60306, ##.##.##.##:443>

Resolution

 

• The fix for this issue is included in vCenter Server 8.0 U3 (8.0.3).

• If an upgrade cannot be immediately performed, involve the Compute Support team to validate the Envoy behavior and assess the possibility of increasing the Envoy connection limit as a workaround.
  Reference: remote https connections exceed max allowed: 2048 in envoy logs of the vCenter server.

• Validate vCenter Server connectivity stability from the HCX Appliance Management UI.

• Re-initiate the failed HCX Bulk Migration jobs.