HCX authentication failed or HCX server is unreachable

Products

• VMware HCX

Issue/Introduction

• HCX Plugin for vCenter does not load the HCX UI, or it takes minutes to load information.
• Direct access through https://<HCX-FQDN>/hybridity/ui/hcx-client/index.html works as expected.
• The following log is found in the vCenter file /var/log/vmware/vsphere-ui/logs/vsphere_client_virgo.log:
  [2025-02-11T09:12:31.187Z] [ERROR] http-nio-5090-exec-12 com.vmware.vcc.rest.RestClient ERROR while authentication to HCX: Unauthorized Access

• In the HAR file it is possible to see the following API response:
  {
    "data": {
        "localEndpoints": [
            {
                "resourceId": "########-####-####-####-############",
                "resourceType": "VC",
                "resourceName": "<vCenter-FQDN>",
                "resourceUrl": "https:<vCenter-FQDN>:443\/sdk",
                "resourceVersion": "7.0.3",
                "hcsp": {}
            },
            {
                "resourceId": "########-####-####-####-############",
                "resourceType": "VC",
                "resourceName": "<vCenter-FQDN>",
                "resourceUrl": "<vCenter-FQDN>:443\/sdk",
                "resourceVersion": "7.0.3",
                "errors": [
                    {
                        "text": "RuntimeException: HCX authentication failed or HCX server is unreachable"
                    }
                ],
                "hcsp": {
                    "serverUrl": "https:<HCX-FQDN>:443",
                    "serverAddress": "<HCX-FQDN>",
                    "version": "4.10.3.24447631",
                    "pluginVersion": "4.10.3.24447631"
                }
            }
        ]
    },
    "success": true
}
• The following log is found in the HCX file /common/logs/admin/web.log:
2025-02-11 10:55:27.447 UTC [https-jsse-nio-127.0.0.1-8443-exec-4, , , TxId: ] WARN  c.v.vchs.hybridity.api.LoginUtil- Failed to get domain and alias map
com.vmware.vim.sso.admin.exception.ConnectionException: java.net.UnknownHostException: <vCenter-FQDN>: Temporary failure in name resolution
  

Cause

This issue is caused by DNS issues where the HCX Manager is not able to resolve the vCenter FQDN/IP.

Resolution

Investigate for possible DNS issues in the environment.

Additional Information

How to generate HAR file