VM replication syncrhonization status is 0KB in VMware Cloud Director Availability

Products

• VMware Cloud Director

Issue/Introduction

• Creating a new replication in VMware Cloud Director Availability completes successfully, but the synchronization is not progressing.
• In the ESX logs for the host running the source virtual machine, entries similar to the following occur repeatedly:
  
  2025-10-29T00:48:56.903Z Wa(180) vmkwarning: cpu11:84402002)WARNING: Hbr: 571: Connection failed to ###.##.###.### (groupID=H4-########-####-####-####-############): Timeout
...
2025-10-29T00:48:56.904Z Wa(180) vmkwarning: cpu11:84402002)WARNING: Hbr: 5362: Failed to establish connection to [###.##.###.###]:44046 (groupID=H4-########-####-####-####-############): Timeout

Environment

VMware Cloud Director Availability 4.7.x

Cause

The source ESX host is unable to establish the required connection with VMware Cloud Director Availability to transmit the synchronization data.

Resolution

Confirm that all required network ports are opened between ESX and VMware Cloud Director Availability. For more information regarding the network requirements, please refer to the following:

Network requirements and prerequisites in the Cloud Director site

Deployment requirements for the On-Premises to Cloud Director Replication Appliance

Please note: if the ESX host is configured with a dedicated vmk for vSphere Replication and vSphere Replication NFC traffic, this interface will be used for replication traffic instead of the management vmk, by design, and the port requirements will need to be configured for this network.