Here are the steps for you:
1. Please make sure DVR or NVR has connected to the router and Internet successfully. You can judge by the picture below.
If it always keeps disconnected, please follow the below instruction to do the troubleshooting:
You had better use Gmail, not Yahoo or Hotmail.
2. Please enable alarm and email alerts function.
3. Please log in to your Gmail account.
4. Please open the website below
5. Please tick turn on.
6. Please set up an email in the DVR setting like the picture below. If the mail test succeeds, it is working.
The SMTP server is smtp.gmail.com
The Port is 465/587
Tick the SSL
The user name is your Gmail account
The password is your Gmail account password
The sender is your Gmail account
The receiver can be any email.
If the mail testing succeeds, you will receive the email notification for the motion detection of the cameras.