Groovy script help- Custom Notification in Case Management

Summary:

Hi, my client is using relationship types for contacts in access groups and would like to trigger a notification to a user when they are added as a contact and the contact case relationship type is Investigating Officer, I have tried the following scripts that aren't triggering the notification. Any guidance would be great, TIA

After changes posted to database:

try {    println("Trigger: After changes posted to database");    // Check if the relationship type is Investigating Officer    if (RelationshipCdMeaning == 'Investigating Officer') {        def map = new HashMap();        def messageText = "You have been added as an Investigating Officer for Case: " + CaseNumber;        map.put("MessageText", messageText);        map.put("RecipientPartyId", PartyId);        map.put("ObjectCode", "CaseVO");