"The following non-configurable port(s) are already in use:2016, 7475, 7476" error while upgrading from Windows vCenter Server 6.5 to 6.7

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:
When upgrading from Windows vCenter Server 6.5 to 6.7, you see similar error during upgrade pre-check:

The following non-configurable port(s) are already in use:
2016, 7475, 7476
Stop the process(es) that use these port(s).

Environment

VMware vCenter Server 6.7.x

Cause

This issue occurs when vmware authentication proxy service is started in vCenter Server 6.5 during the upgrade.

Resolution

To resolve this issue, stop VMware vSphere authentication proxy service.