Symptoms:
The VIC plugin installer script runs and reports successful. After restarting the web client services the VIC plugin does not load. The logs on the vCenter /var/log/vmware/vsphere-ui/logs/vsphere_client_virgo.log report error downloading the plugin zip.
[2018-02-20T13:46:16.805-05:00] [WARN ] vc-extensionmanager-pool-62 com.vmware.vise.vim.extension.VcExtensionManager Package com.vmware.vic was not installed. Error downloading https://<VIC_Appliance_FQDN>:9443/files/com.vmware.vic-v1.3.0.533.zip. Make sure that the URL is reachable then logout/login to force another download.
[2018-02-20T13:46:16.805-05:00] [WARN ] vc-extensionmanager-pool-61 com.vmware.vise.vim.extension.VcExtensionManager Package com.vmware.vic.ui was not installed. Error downloading https://vpviclbal800.techlab.susq.com:9443/files/com.vmware.vic.ui-v1.3.0.533.zip. Make sure that the URL is reachable then logout/login to force another download.