While working on my Test Lab I recently came across this issue where Once I opened the vCenter Web client or Vsphere Client (Flash) and tried to login

vSphere Client is a software application developed by VMware that allows administrators to manage VMware vSphere environments. It provides a graphical user interface (GUI) through which administrators can perform various tasks related to virtual machine management, host configuration, networking, storage, and more.

I got the below Error:

vSphere Client (Flash): [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: Responder, sub status: null.

Web Client (HTML 5) : [400] An error occurred while processing the authentication response from the vCenter Single Sign-On server. An error occurred while processing the metadata during vCenter Single Sign-On setup – java.lang.reflect.InovocationTargetException

Below are the Screenshots of the Error:

While reviewing the Setup I noticed the below Difference in the PSC and vCenter Server.

I SSH to the PSC and Checked the Time using the below Command:

Date

PSC SSH:

vCenter SSH:

Here is My System Time:

So definitely there was a mismatch in the Time between the vCenter and the PSC.

I thought this is not right and I went into the PSC VAMI and found the Timezone as my Own i.e. IST.

However while looking into the vCenter VAMI I can see the Timezone set as GMT-10.

So I just changed the Timezone of the vCenter appliance to IST 

Now I can open the vCenter Appliance without any issues.

Hope this article has clarified your doubts in case if you came across this issue.