Follow the steps on how to setup a vCenter instance:
Verify that at a minimum, the user account must have Read privileges and the Read privileges must be assigned at the data center or vCenter Server level.
Ensure you have setup DNS and NTP properly.
Thank You RickVerstegen for the article.
Given article is working fine to add local vCenter Instance;
We're able to add local vCenter Server (on which the vRealize Operations Manager Appliance is running), but while adding remote vCenter Server or vCenter Server having difference IP range or subnet (of vRealize Operations Manager Appliance), getting this error.
Please suggest if any specific ports needs to open from vRealize Appliance or vCenter instance.