Your line:
/tool e-mail send to="admin@example.com" subject="High Traffic Alert" body="Traffic on ether1 exceeded 1MB!"
Doesn't tell the system what email server or port needs to be used when sending emails. Have you configured the SMTP server settings for your system?
Take a look at
this page for more information on configuring the SMTP server settings on your MikroTik.
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Backups are your friend. Always make a backup!
/system backup save encryption=aes-sha256 name=MyBackup
Please, export and attach your current config to your post if you want help with a config issue:
RouterOS v6 code
/export hide-sensitive file=MyConfig
RouterOS v7 code
/export file=MyConfig