Characteristic & missing from report

What causes this issue?

Period characteristic &V1& is not used in the checked report. However,
based on the settings of the assigned Report Writer table or key
figures in use, this characteristic has to appear in the report.

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?

Enter characteristic &v1& at a fitting position in the report
definition.

Error message extract from SAP system. Copyright SAP SE.