Mailtrack is one of the most reliable and accurate email tracking solutions in the market, our reliability is much higher than our competitors and we keep improving it, however, the tracking technology has some limitations.
There are two main causes of inaccuracy:
1) Emails to yourself don't work well.
If you send emails to yourself Mailtrack can't work well, so please, don't test Mailtrack by sending an email to yourself, but to someone else. If you use different emails, don't use the same computer to send the email with Mailtrack and to open the email.
2) A small percentage of users are not trackable
In some cases, your email has been opened, but Mailtrack says it is not opened. This can happen to a small percentage of emails sent with Mailtrack. The main reason is that some email clients (e.g. Outlook) don't show images inside emails by default, so Mailtrack pixel it is not opened. This problem not only affects Mailtrack, but for any email tracking software and email marketing tools. Without images no tracking is possible.
The good news, though, is that this not showing images by default is becoming a thing of the past. In fact, Gmail shows all images by default since 2014. Most of email clients followed Google and are also showing images by default. Those changes improved considerably Mailtrack accuracy and we expect our accuracy to be increased in the near future.
Anyway, sorry for the inconvenience that those limitations in accuracy may cause you.