Ensure network connectivity can be established from the impacted vCenter server to the plug-in download URL noticed in vsphere_client_virgo.log
Workaround:
vc-packages folder location for the plug ins published to web client as vCenter Extensions:
vCenter Server that runs on Windows: C:\ProgramData\VMware\vCenterServer\cfg\vsphere-client\vc-packages
vCenter Server Appliance : /etc/vmware/vsphere-client/vc-packages
cm-service-package folder location for the plug-ins published as SSO service:
vCenter Server that runs on Windows: C:\ProgramData\VMware\vCenterServer\cfg\vsphere-client\cm-service-packages
vCenter Server Appliance : /etc/vmware/vsphere-client/cm-service-packages
Note: copy the folders to some other location as backup and avoid renamed backup folders in the same location
pickup and work folder location:
vCenter 6.0 that runs on Windows:
C:\Program Files\VMware\vCenter Server\virgo\server\pickup
C:\Program Files\VMware\vCenter Server\WebClient\server\work
vCenter Server Appliance 6.0:
/usr/lib/vmware-virgo/server/pickup
/usr/lib/vmware-vsphere-client/server/work
vCenter 6.5 and 6.7 that runs on Windows:
C:\programdata\VMware\vCenterServer\runtime\vsphere-client\server\work
C:\programdata\VMware\vCenterServer\runtime\vsphere-client\server\pickup
vCenter Server Appliance 6.5 and 6.7:
/usr/lib/vmware-vsphere-client/server/pickup
/usr/lib/vmware-vsphere-client/server/work
If this issue persists, contact VMware Support