You may create an alert to to send email notifications when someone logons or RDP to a domain controller following the steps below:
1- Go to Auditing & Alerting > Alerts.
2- On the top menu click "New" and then click Next.
3- Provide a name for this new alert, for example DC logons. Adding a description or alert priority is optional.
4- Click Next.
5- Add an email, or email distribution list for receiving the alerts and click Next.
6- In filter event definitions field type "logged", select the event definitions that are displayed and click next.

7- Click "Next" 4 times and then click "Finish" twice.
Once the above alert is created you should be able to see it at the bottom of the alert list.

RDP to one of your domain controllers as a test and see if you receive the email notification.
If you still do not receive any email notification for the logon events, then close your Active Administrator console, open windows services, stop and start your active administrator services in the following order:
1- Active Administrator Foundation Service.
2- Active Administrator Data Service.
3- Active Administrator Notification Service.
4- Active Administrator HTTP Service.
Open the console and test again. You should be receiving your DC logon email alerts successfully.