Status of main condition record reset (see long text)

What causes this issue?

The status of a period condition record has been reset to "active". Any
existing settlement document resulting from final settlement accounting
will remain in existence.
The status of the main condition record, which was also marked as
"inactive" (settled), has also been reset. This permits any necessary
renewed final settlement.

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?

If provision for this has been made in Customizing for the settlement
type, final settlement accounting for the main condition record can be
carried out again. In the process, the income from interim settlements
will be set off against the total sum due.
Check whether or not you wish to cancel any existing settlement
document resulting from the final settlement accounting.
If no provision has been made for final settlement, the main condition
record will be deactivated again when settlement accounting has been
effected for the last period.

Error message extract from SAP system. Copyright SAP SE.