Source system & not of type file or external system

What causes this issue?

Source system &V1& is neither a file system nor an external system.

System Response

The source system is not imported.

How to fix this error?

Create the source system in the Data Warehousing Workbench.
If follow up errors occurred during import due to the nonexisting source
system, reimport the request. Note also the correct maintenance of the
V_RSLOGSYSMAP view.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.