Message SAP /MAP/F108 - Source characteristic &1 must be limited to single value in selection

Diagnosis
the characteristic &V1& has been defined as a source characteristic inthe parameter group. Source characteristics must be a part of theplanning level and be limited to a single value in the selectioncondition.
The characteristic &V1& is not limited to a single value.

System Response
The system cannot execute the planning function.

Procedure
Limit the characteristic &V1& to a single value.