Combination of DOCTYP and CIMTYP fields is invalid

What causes this issue?

In the control record of the IDoc to be stored, fields DOCTYP and
CIMTYP have the values &v1& and &v2& respectively. Field IDOCTP,
however, is blank. This combination is invalid, because in general an
extension must be assigned to a basic type (in field IDOCTP).

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?

Please inform your system administration.

Error message extract from SAP system. Copyright SAP SE.