Fiscal year variant field is not assigned to an infocube field

What causes this issue?

You use the posting period (field <ZH>SPBUP</>) as one of the
periodicities in your planning scenario. You must specify the posting
period using the fiscal year variant (field <ZH>FISCVARNT</>).
The list of assignments to infocube fields currently contains such an
entry but it is not assigned to an infocube field.

How to fix this error?

Goto maintenance for BW-specific settings at the planning level for
planning scenarios. Assign the relevant infocube field to the fiscal
year variant field.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.