VCenters status showing unknown on the orion web console

Hi All,

We are currently running SolarWinds OrionPlatform-v2015.1.2-HotFix5, NPM SolarWinds-NPM-v11.5.2, IVIM 2.1 and VMAN-v6.3.0-HotFix1

I am trying to add our Virtual Center server to NPM. created credentials in VCenter with RO access.

When I supply these credentials and "Poll for VMware" the test is successful. 

I am facing major issue vcenter discovery through NPM ,Most of the VCenters status showing unknown on the orion web console. even i had open  case  898072 with SolarWind but no response comming from LAB

Regards'Om