"Could not connect to one or more vCenter Server Systems" is reported on vSphere Client 9.x

Products

• VMware vCenter Server

Issue/Introduction

• Login to vSphere Client for vCenter 9.x in linked/grouped vCenter Server (VC) displays banner "Could not connect to one or more vCenter Server systems:https://<VCSA>:443/sdk Login failed due to invalid credentials"
• The error includes all VC servers part of vCenter Groups
• /var/log/vmware/vsphere-ui/logs/vsphere_client_virgo.log:

[YYYY-MM-DDTHH:MM:SS] [INFO ] wcp-plugins-notifier-1        c.v.v.plugin.notification.WcpServicePluginNotificationsListener   Updating WCP plugin subscriptions...
[YYYY-MM-DDTHH:MM:SS] [WARN ] wcp-plugins-notifier-1        com.vmware.vsphere.client.security.impl.LookupServiceVcSource     Duplicate VC URLs found: [https://<VC FQDN>:443/sdk]
[YYYY-MM-DDTHH:MM:SS] [ERROR] wcp-plugins-notifier-1        c.v.v.plugin.notification.WcpServicePluginNotificationsListener   Unable to subscribe to vc <VC FQDN> (<VC adapter ID>), nodeId: <VC Node ID> com.vmware.vapi.client.exception.HttpProtocolException: HTTP response with status code 502 (enable debug logging for details): upstream connect error or disconnect/reset before headers. reset reason: protocol error
        at java.base/java.lang.Thread.getStackTrace(Unknown Source)

• Log in to the <VC FQDN> via ssh reported in the above log and execute the below command:

/usr/lib/vmware-vmafd/bin/vmafd-cli get-ldu --server-name localhost

Environment

vCenter 9.x

Cause

This issue occurs when a stale configuration entry remains from a decommissioned vCenter Server that was subsequently redeployed using the identical FQDN (Fully Qualified Domain Name) within the same vCenter Group

Resolution

In order to cleanup the stale entry the vCenter Group needs to be recreated

1. Log in to VCF Operations UI
2. Navigate to Infrastructure Operations -> Configurations -> vCenter Linking
3. Click on the Group Name
4. Select all vCenter -> Click DELETE
5. Proceed to CREATE GROUP and add the vCenter Instances