Phys. inv. doc. cannot be created before period &/&

What causes this issue?

The specified date lies before the previous period. However, you can
only enter a physical inventory document for the previous period, the
current period, or the next period.

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?

Change the planned count date.

Error message extract from SAP system. Copyright SAP SE.