In the activity Define General Settings for Partner/Product Range, you need to check the indicator Check PPRs in Business Transactions and Applications and set the PPR Type for Marketing Planner to 0012 Marketing Planner.

In the activity Define Partner/Product Range Types, you need to check the indicator Use in PPR Check for type 0012.

In the activity Define Transaction Types and Applications Relevant for Check, add MKPL in the second folder Applications Relevant for the PPR.