In single emails sent to more than one person (e.g. a group of people), Mailtrack isn’t able to identify the individuals that have opened the email or not.
The reason for this being that tracking multiple people in a single email affects the deliverability of your emails: For example, your messages could be classified as Spam or send to Promotions tab. Essentially, your emails will be less opened.
Technically speaking, group email tracking requires the setting up of your own email servers, as Gmail (Google) servers cannot be used to provide this functionality. It is unlikely, however, that your own emails servers will be as reliable as the Gmail (Google) ones.
We apologize profusely, but for these reasons, we prefer not to offer a service that is not reliable and will affect the deliverability of your emails.
The easiest workaround to this limitation is to send separate emails to each person. Response and open rates for group emails are lower than for emails to individual recipients, so our recommendation is to avoid them.
It makes sense to send group emails internally inside your company, but in that case, you can ask your colleagues to install Mailtrack, as in this instance Mailtrack will provide reliable tracking data for group emails.