I've had a successful email campaign series setup using Universal Analytics with the /collect img code for open rate, except there are two emails that are mysteriously not tracking.
Tracked opens properly:
<img src="http://www.google-analytics.com/collect?v=1&tid=UA-5406459-1&cid=36200&t=event&ec=email&ea=open&el=1a5fc002&cs=newsletter&cm=email&cn=Public+Invite+Open&cm1=1" />
Did not track opens:
<img src="http://www.google-analytics.com/collect?v=1&tid=UA-5606459-1&cid=36200&t=event&ec=email&ea=open&el=1a5fc002&cs=newsletter&cm=email&cn=Newsletter+2014+03+Open&cm1=1" alt="">
...and the other was cn=Newsletter+2014+02+Open, the similarity of which makes me wonder if it is something so simple as the naming convention of the campaign. However I can't find locate anything about disallowed names.
