You do not have sufficient privileges to delete "Your OU Name", or this object is protect from accidental deletion.

You do not have sufficient privileges to delete "Your OU Name", or this object is protect from accidental deletion.

To fix this error:

Open Active Directory Users and Computers -> Click View -> Advance Features

Right click the OU and click properties

Select the Object Tab

Uncheck Protect object from accidental deletion

Now try to delete the OU