Re: Can not logon to vCenter Webservice

http://pubs.vmware.com/vsphere-51/topic/com.vmware.vsphere.install.doc/GUID-6BDE5582-DFCD-4D2D-BD09-016B2C4D1CF7.html

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By default, the user admin@System-Domain can log in to the vSphere Web Client and vCenter Server

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Here the username is "admin@system-domain" which is the default user account for SSO/Single Sign On