Termination date &1 is invalid

What causes this issue?

The error was caused by one of the following:
The date you entered is after an existing proration date.
The termination date is before the actual allocation date.

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?

INCLUDE ISU_KORR OBJECT DOKU ID TX

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.