Receiver & is not plan integrated

What causes this issue?

The receiver is not plan-integrated. Planned settlement is only
possible, however, if the senders and receivers are plan-integrated.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check the settlement rule for the sender.
Note:
The "plan-integrated" characteristic is stored in the master record for
the internal order or WBS element and cannot be changed later.
If the receiver is a real estate object: Business function
RE_CO_INTEGRATION must be activated for integrated planning and
integrated planning for real estate objects must be activated in the
configuration of the plan version.

Error message extract from SAP system. Copyright SAP SE.