CO area & has invalid period version &

What causes this issue?

You assigned fiscal year variant &V2& to controlling area &V1&. This
fiscal variant does not exist.

System Response

Postings from controlling area &V1& are not permitted if a posting
period cannot be determined from the posting date because the fiscal
year variant is invalid.

How to fix this error?

Assign a valid fiscal year variant to controlling area &V1&.

Error message extract from SAP system. Copyright SAP SE.