In cases where vCenter Server plug-ins are not working, you have several options to correct the problem. vCenter Server plug-ins that run on the Tomcat server have extension.xml files, which contain the URL where the corresponding Web application can be accessed.
These files are located in
C:Program FilesVMwareInfrastructureVirtualCenter Serverextensions
Extension installers populate these XML files using the DNS name for the machine.
vCenter Server, plug-in servers, and the vSphere Clients that use them must be located on systems under the same domain. If they are not under the same domain, or if the DNS of the plug-in server is changed, the plugin clients will not be able to access the URL, and the plug-in will not work.To resolve this problem you can edit the XML files manually by replacing the DNS name with an IP address. Reregister the plug-in after you edit its extension.xml file.