If the network connection between the VMware vCenter Server and a VMware vSphere Client is lost while any of the following operations are being performed, the error message may be become an empty string ("") or "Error" may be displayed in the Error Dialog.
Check that there are no problems with the settings of the browser.
Check whether the URL of the ROR console has been added to the "Trusted sites" of the web browser.
For details, refer to "Chapter 2 Login and Logout" in the "User's Guide for Infrastructure Administrators CE"
