DataSource &1 not found

What causes this issue?

The DataSource '&V1&' either does not exist or is not assigned to a
planning area.

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?

You can rectify the problem by regenerating the DataSource. Use the
appropriate functions for this purpose.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.