Issue: Real-time open notifications aren't displaying on your Android phone when a tracked mail is opened.
Explanation: The Real time notifications on your phone feature isn't enabled in your Mailtrack settings (this FAQ explains how you can check to see whether it's enabled).
Either that or notifications are not enabled in Chrome on your phone. To verify this:
1) On your Android phone or tablet, open the Chrome app.
2) Tap More (the three vertical dots) in the browser toolbar, then Settings.
3) Tap Site Settings and then Notifications.
4) Turn the setting on if that's not already the case.