Notification is sent to employee only after SR ticket is assigned to Agent

Hello team,

We are getting an issue where an User initiates a SR and doesnt get any notification is assigned, which is already configured. When an agent is assigned the then only the notification is triggered to both agent and employees. Please find the below groovy script used in before update trigger event.

if (isAttributeChanged('AssigneeResourceId')) {
try {
def recipientPartyId = AssigneeResourceId
def messageText = 'An SR notification (default message).'

    if (recipientPartyId) {

     //Call to send notification

        adf.util.sendNotification(adf, messageText, recipientPartyId)


   //Log a confirmation that the notification has been sent. Logs can be viewed in 'Runtime Messages'.

 //println("Notification sent to " + recipientPartyId + " because the SR was assigned to them.")