Error on WWI server &1: Writing the source document failed

What causes this issue?

The source file for generation could not be written to the &V2&
directory on the WWI server &V1&.

System Response

Generation was not carried out.

How to fix this error?

Check on the WWI server &V1& if the &V2& directory is present and can be
written in.
Check the Windows event log on the WWI generation server. The event log
may contain other error messages.
Note 1058521 provides possible remedies for the error that occurred.

Error message extract from SAP system. Copyright SAP SE.