The email feature needs to use the SSL/TLS or STARTTLS encryption protocols and you have to enable them or configure the email service to allow connection from a third party application (eg. POP/IMAP settings in Gmail). I have set up email for my NVR as well and just tested it and it works.
Try switching to the Gmail service and enable the settings if you can't do it for your own account.
Here is some info about this: https://support.google.com/a/answer/176600?hl=en