Status-relevant planned record for activity &1 not deleted (-> long text)

What causes this issue?

You want to delete a status-relevant correspondence planned record for
the previous transaction activity &V1&. You are not allowed to do this
here, since it can lead to inconsistencies in the confirmation and/or
counterconfirmation status of activity &V1& (another financial
transaction activity is currently active).

System Response

The system does not allow you to delete the correspondence planned
record.

How to fix this error?

If you need to delete old, status-relevant correspondence planned
records, you should check your transaction process. You may find that
your Customizing settings or standing instructions are incorrect.
You can delete correspondence planned records from the
<DS:TRAN.TBZ11>Correspondence monitor</> consistently, irrespective of
the active or previous transaction activity.

Error message extract from SAP system. Copyright SAP SE.