Delivered/invoiced quantities cannot be updated in CO

What causes this issue?

For account assignment object &V1&, the delivered or billed quantity is
to be updated in the unit of measure &V3& for material number &V2&.
The system has found a totals record (COSL) that already exists for the
account assignment object &V1& with unit of measure &V4&. However, you
cannot convert the quantity from &V3& to &V4&.

System Response

The quantity cannot be updated in the totals record, <ZH>which means
that the quantity is missing for the receiver after the settlement of
&V1& (for example in CO-PA).</> Only the posted quantity is saved in
the CO line item (COEPL table).

How to fix this error?

Change the material &V4& and define &V4& in the master data record as
an additional unit of measure.
If you can have the quantity in &V3& in the COSL totals record without
it causing any problems, you can deactivate this error message in
customizing, or change it to a warning or information message.
To do this, see the implementation guide (IMG) for "General
Controlling" under the following activity:
<DS:SIMG.SIMG_CFMENUORK3OBA5>Change Message Control </> (work area KI,
message no. 137).
If you have any questions, contact your CO consultant.

Error message extract from SAP system. Copyright SAP SE.