Error: Failed to send notification: E-mail configuration invalid or disabled.
When perform any type of activity with Notification scheduled
1. The DS-Client cannot connect to the E-mail server
2. The Global Notification (DS-User > Setup > Configuration > Notification ) was disabled but remains the backup set email notification (Backup Set Properties > Notification tab > Modify the existing config.
1. Check E-mail settings and if E-mail server is available. Ping the email server to see if it is still up.
2. If the Global notification was disabled, then disable the backup set notification as well.