How To Fix WXP012 - Errors occurred in the key figure formula type "during selection"

SAP Error Message - Details

• Message type: E = Error

• Message class: WXP - Retail Planning

• Message number: 012

• Message text: Errors occurred in the key figure formula type "during selection"

What causes this issue?

In this planning layout, key figures are used whose values are
calculated using key figure formulas.
Errors occurred in these calculations. Verify which key figures are
proving to be problematic.
To do this, use the "Check key figure formulas..." under "Extras".

System Response

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

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.