2558044 - Error: Cannot delete cost center 9999; it is the responsible unit of a project

When you are trying to activate the Org Structure, you receive below error message:

Cannot delete cost center 9999; it is the responsible unit of a project.

1. Go to Organizational Management workcenter.
2. Select Org Structure view.
3. Select the required Org Unit and Edit.
4. In the Planning Area, make required changes in the Org Unit and Activate.
   You receive above error message.

The Org Unit: 9999 is available in the Active Area as Unlimited.
But this Org Unit was Delimited in the Planning Area since DD.MM.YYYY in the past.

Update the Org Unit : 9999 again as Cost Center and Delimit it with a future date.

Cost Center; Activate Org Structure , KBA , AP-OM , Organisational Management , Problem