Storage of values not possible for key figure &

What causes this issue?

The key figure &v1& is not an internal type D, T or C, that is,
it does not concern a key figure for date or time or a key figure that
can accept character values.

System Response

The function <LS>values for key figure</> cannot be used here.

How to fix this error?

If you would like to save multiple requirements for a key figure,
enter the requirements on the screen or use the function
<LS>duplicate</>.

Error message extract from SAP system. Copyright SAP SE.