When resetting a mobile device to factory settings it could be that our licensing system recognizes your device as a new device after the factory reset.
If Emsisoft Mobile Security is already installed on the device after the reset and you're having trouble activating it, please uninstall Emsisoft Mobile Security, then log in with your Google email address at the following site: https://central.emsisoft.com/
Choose "My devices" from the menu on the left. You should see two entries for mobile devices there; please remove both of them by clicking the three little dots in the upper right corner of these entries and then choosing "Remove".
Now please click the blue button "Install Emsisoft Mobile Security" in the upper right also under "My devices". Proceed to enter your email address, and we'll send you an email. Check your email using your mobile device and click the Google Play sign in the message to re-install Emsisoft Mobile Security on your mobile device this way.