KB8404: The "Define Subscription Preference" option is grayed out in MicroStrategy Narrowcast Server 9.x and newer

SYMPTOM:
When users attempt to define the subscription preference for users at the subscription set level, the "Define Subscription Preference" option is greyed out. This occurs even though option to define user preferences at the user level is available, as shown below:
 

CAUSE:
This issue occurs because the subscription set has not yet been associated to a service with an information object containing a prompt.
ACTION:
In order for this section to be enabled, the subscription set needs to be associated with a service so that the subscription set can read which Information Objects belong to that service and which Information Objects will be able to be defined.
NOTE: The Information Object must contain a prompt.
Perform the following steps to resolve the issue:

1. Create a service which contains a publication and associate a schedule and Subscription set to that service.
2. After step 1, the option to Define Subscription Preference within the subscription set will be available.