Creation of several supplier line items is not possible for doc. type &

What causes this issue?

The document type entered results in a net posting. Further processing
of several supplier line items within a single invoice document is not
supported for this type of posting.

System Response

The document cannot be processed further.

How to fix this error?

If you are in create or change mode:
Either use a document type which results in a gross posting or create
only one supplier line item within this document.

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

If you are in display mode:
On the basis of the document type selected, this document does not
contain any splitting information, so displaying it is not possible.

Error message extract from SAP system. Copyright SAP SE.