Diagnosis
The sales period of the plant group falls outside the sales period ofthe whole promotion (earliest start of sale and latest end of sale forall plant groups).
A module has already been created for this promotion. The validityperiod of a module that corresponds to the listing period of thepromotion cannot be changed.

Procedure
You can only change the validity period by deleting all modules,changing the listing period, and then creating new modules.
You can only delete modules if subsequent processing has not yet beencarried out.