I send newsletters from my Drupal 7 site, using the Simplenews module. I'm using this tracking code, but it isn't tracking uniqueness:
<img src="http://www.google-analytics.com/collect?v=1&tid=test- 1&cid=123445678&t=event&ec=email&ea=open_my_newsletter_june2016&el=recipient_id&cs=newsletter&cm=email&cn=Campaign_Name">
I change the tid
according to my Google Analytics account and the ea
attribute to the name of my newsletter and the date, but these aren't unique URL's for users.
How can I track unique opens of my newsletter, using Google Analytics?