Vrealize 7.0 integration with Active directory

Hi

I am doing a deployment of VRA 7.2

I have used windows 2012 R2 standard  as AD and Windows 2008 R2 for Iaas server

All the service in VRA and Iaas server are up and running  and i am able to login successfully

I face issue when i try to add the directory from Administration > directory  .

I am using the Active Directory ( Integrated Windows Authentication ) and logged in to tenant using Tenant Administrator

I know my domain admin is correct because same i used to add other computers to domain.

But in this case when i try to add the directory i am getting the error

"Could not join domain: Error occurred while joining domain. Verify Domain Admin username and password is correct, and the username is the sAMAccountName."

I know the credentials are correct and have the the required priveledge

Any specific AD config i need to do here