Hi,
One of the possible reason's could be : --
Your SEPM may not have a directory server address with which to synchronize AD OUs.
The imported OU may have not been synchronized yet with new AD (Active Directory) members, and/or replication has not yet occurred with other SEPMs.
Setting up connections between management servers and clients
On the Policies tab, uncheck Inherit policies and settings from parent group Note: You cannot set any communication settings for a group unless the group no longer inherits any policies and settings from a parent group.
Under Location-independent Policies and Settings, in the Settings area, click Communication Settings
In the Communication Settings for group name, under Management Server List, select the management server list. NOte: The group that you select then uses this management server list when communicating with the management server.
Click OK