Exactly &1 serial numbers must be selected (instead of &2)

What causes this issue?

You or another user have entered an incorrect number of serial
numbers.
The maximum number of <DS:GLOS.serial_number>serial numbers</> may equal
the amount of document items. If there is a serial number obligation,
this must equal the document quantity.

System Response

INCLUDE KEINE-FUNKTION OBJECT DOKU ID TX

How to fix this error?

Delete the serial numbers or add further serial numbers.

Error message extract from SAP system. Copyright SAP SE.