You use planning strategy Finite Scheduling with Reverse and want to allow scheduling the past.

The planning strategy Finite Scheduling with Reverse allows you to schedule production orders backwards from the requested delivery date, taking into account the available capacity and material constraints. To allow scheduling the past, you need to specify a negative offset time in the strategy profile. The offset time defines how far in the past the system can schedule the production order start date. For example, if you specify an offset time of -5 days, the system can schedule the production order start date up to 5 days before the current date. This can help you to avoid late deliveries and reduce lead times.

References: [SAP S/4HANA Production Planning and Manufacturing Certification Guide], page 97; [SAP Help Portal: Finite Scheduling with Reverse]