Symptoms:
A server error occurred.
[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.
Check the vSphere Web Client server logs for details.
The %ALLUSERSPROFILE%\VMWare\vCenterServer\logs\sso\vmware-sts-idmd.log file contains errors similar to:
[YYYY-MM-DDT<time> vsphere.local c006bcab-####-####-####-########251 INFO ] [VmEventAppender] EventLog: source=[VMware Identity Server], tenant=[vsphere.local], eventid=[USER_NAME_PWD_AUTH_FAILED], level=[ERROR], category=[VMEVENT_CATEGORY_IDM], text=[Failed to authenticate principal [vcenter@domain]. Access denied], detailText=[com.vmware.identity.idm.IDMLoginException: Access denied
</time>
This issue occurs when the domain in which the user you are attempting to log in does not exist as a VMware vCenter Single Sign-On identity source.