Configuration of serial number & incompatible with document item

What causes this issue?

You tried to assign a serial number with an unsuitable configuration to
a configured document item.
However, you are only allowed to assign the following serial numbers:
A serial number that is unconfigured
A serial number whose characteristics and values are completely
identical to those of the configured document item

System Response

The serial number is not taken into consideration.

How to fix this error?

Check the configuration of the serial number or assign a different one.

Error message extract from SAP system. Copyright SAP SE.