Why can't I receive emails in my mailbox after email notifications are set for the TOS system?

This is probably because the default SMTP mail server port for the TOS system is blocked. You can change “Default SMTP Mail Server” to “Custom SMTP Mail Server” in the “Advanced Settings” interface of this page, and then perform related configurations. For example, if using Gmail the settings for the outgoing server are:

Outgoing server (SMTP): smtp.gmail.com

Port: 465

Protocol type: TLS/SSL