Use Gmail as an example:

Gmail settings:

1. Please login your Gmail and go to go to Settings --> Forwarding and POP/IMAP --> Enable POP and IMAP --> Save Changes.

2. Click Google Account on top right corner, choose Manage your Google account.

3. Click Security on left side. Click on 2-Step Verification and follow it to turn on 2-step Verification. (If you’ve enabled 2-step Verification jump this step.)

4. Go back to google account security settings, refresh the page, you will see App passwords under 2-step Verifictaion.

5. Click on App passwords. Click Select device, choose Other and set a name yourself. Then click GENERATE to get a APP password.

NVR Settings：

1. 1.Right click on NVR monitor, choose Menu--> Network--> Basic--> Email.
2. 2. Type in the sender and recipient information and click Apply.
3. 

4. (The information on the picture above is just an example)

5. 3. Click Test to verify the email settings.
6. (Please check with your email supplier if you have troubles in email SMTP configuration)
7. 4. Click Alarm--> Motion, select camera and click behind Trigger Actions.
8. 
9. 5. Check in Send Email, click Apply and OK.
10. 

11. Tips: You just enabled Send Email for the selected camera, please select other cameras and do the same steps to enable Send Email for them.

12.  

13.