Fiscal year variant is missing in controlling area &

What causes this issue?

No fiscal year variant was assigned to controlling area &V1&.

System Response

The R/3 System requires a fiscal year variant in order to determine the
posting periods and fiscal years to be processed, as the master records
are time-dependent. No master data can be maintained in controlling
area &V1& because the fiscal year variant is missing.

How to fix this error?

Assign a fiscal year variant to controlling area &V1&, or use another
controlling area.

Error message extract from SAP system. Copyright SAP SE.