No substitution for item &1/&2 with "rules immediately"

What causes this issue?

The system could not determine any substitutions when executing
rules-based ATP for the item &v1&/&v2& using <DS:DE./SAPAPO/RULSC>Start
immediately</>.

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?

Check the rules used in rules-based ATP for the following:
Substitution procedures
Sequence in the rule control
Ensure that the location products that you defined in the substitutions
have been entered in the location-specific product master.
To do so, use the rule evaluation in integrated rule maintenance.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.