The master record for allocation cost element & has not been found

What causes this issue?

You would like to plan an activity input from the sending object with
the object number &V2&. For this object, the allocation cost element
&V1& was determined within the activity type planning in the fiscal
year &V3& for the version &V4&.
A valid master record does not exist for the allocation cost element.

System Response

Processing was cancelled.

How to fix this error?

Find out whether allocation cost element &V1& in fiscal year &V3& does
not actually have a master record. You can create one at a later time
and thereby solve the problem.

Error message extract from SAP system. Copyright SAP SE.