Pattern IDoc written to database. Not defined for processing.

What causes this issue?

The IDoc was created using the IDoc test tool and subsequently
simultaneously saved in the IDoc database and as a file in the file
system of the operating system.
The user of the test tool was '&v1&'.

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?

Error message extract from SAP system. Copyright SAP SE.