Accessing the vCenter UI results in a circle spinning on the screen, and the UI is never loaded

Products

• VMware vCenter Server

Issue/Introduction

• When attempting to access the VCSA UI, the browser does not display any output or is stuck at a loading circle. However, access to the VAMI and SSH work as expected (both via IP and FQDN).
• Opening the Chrome debugger using the F12 key and reviewing the network tab for connections, the following message will be seen:

logging(pending)

• Error message after the UI loads for about 10 to 12 minutes :

[400] An error occurred while processing the authentication response from the vCenter Single Sign-On server. Details: Status:urn:oasis:names:tc:SAML:2.0:status:Requester, sub status: null.

• vCenter server /var/log/vmware/vsphere-ui/logs/vsphere_client_virgo.log will have the following entries :

com.vmware.vim.vmomi.client.exception.ConnectionException: http://localhost:1080/external-vecs/http2/vCenter-FQDN/443/sso-adminserver/sdk/example.local invocation failed with "java.net.SocketTimeoutException: Read timed out".

• No session exhaustion is seen in /var/log/vmware/vpxd/vpxd.log.

 

Cause

• DNS server is not able to resolve the vCenter FQDN.
• Recent changes to the DNS servers, such as DNS server migration to different geographical locations.

Resolution

• Change the DNS to the native one where the forward and reverse lookups are working.
• To change the DNS entry on the vCenter from the VAMI page
  • Log in as the root user to the vCenter Server Appliance Management Interface (VAMI) and navigate to Networking > Edit network settings
  • Edit network settings ->  enter DNS settings manually with the same DNS servers listed (If there was any DNS server migration). If not provide the new DNS server IP which is closer in geographical location to the vCenter server.

Additional Information

When session exhaustion is seen in the vCenter server /var/log/vmware/vpxd/vpxd.log below Broadcom KB article will come in handy :

• Could not connect to one or more vCenter Server Systems: https://vCenterFQDN:443/sdk" error in the vSphere Client due to VPXD session exhaust.
• Accessing the vCenter GUI results in a circle spinning on the screen, but no GUI ever comes up.