Error occurred deriving representative material

What causes this issue?

Derivation of representative material &V1&.
The system was unable to find a derivation rule entry when carrying out
the derivation rule for the specified source values.
The derivation rule was set up in such a way that an error message does
not appear.
No derivation rule entry exists for the following source field values:
&V3&
&V4&

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?

Enter a derivation rule entry under <DS:TRAN.8KEO>Maintain Derivation
Rules/Entries</> for the specified source field values. See
<DS:SIMG.SIMG_CFMENUORK18KEO>Derive Representative Materials</>. Make
sure that derivation rule entries are made for all valid source field
values.
If you do not want derivation to be carried out in all cases, you can
define the derivation rule in such a way that no error message appears
if a derivatin rule does not exist.

Error message extract from SAP system. Copyright SAP SE.