Event receiver not attached on production

Event receiver is working fine for all custom lists in development environment.

Issue: When i deploy the same event receiver solution file in production server, it is not firing.

Perform below powershell script

$spWeb = Get-SPWeb -Identity "http://npduat:7001/"

$spList = $spWeb.Lists["DocumentTrackingEmailNotification"]

$spEventReceiver = $spList.EventReceivers.Add()

$spEventReceiver.Assembly = "BFL.PPAP.Webparts, Version=1.0.0.0, Culture=neutral, PublicKeyToken=56fcab577ff38308"

$spEventReceiver.Class = "BFL.PPAP.Webparts.EventReceivers.DocumentTrackingEmailNotificationReceiver.DocumentTrackingEmailNotificationReceiver"

$spEventReceiver.Name = "DocumentTrackingEmailNotificationReceiverItemAdded"

$spEventReceiver.Type = "ItemAdded"

$spEventReceiver.SequenceNumber = 1000

$spEventReceiver.Synchronization = 1

$spEventReceiver.Update()

Refer link