How to add a Directory server in the SEPM console for Active Directory (AD) synchronization.
Select the appropriate OU as desired to integrate with SEPM and click OK.
It will successfully synchronize AD and will integrate with the OU structure.
In case of issues with AD Sync check following logs in C:\Program Files\Symantec\Symantec Endpoint Protection Manager\Tomcat\logs\ADSITask-0.log (for a 64 bit machine the location would be C:\Program Files(x86)\Symantec\Symantec Endpoint Protection Manager\Tomcat\logs\ADSITask-0.log)
Search for "Error Code" and next few lines for the reason.