Failed to send mail: SMTP SERVER GREETINGS ERROR; 421 4.3.2 Service is not available, closing transmission channel.
This error occurs if the Cyberoam is not able to access the Mail Server while configuring Mail Server settings from System > Configuration > Notification. It is displayed in Logs & Reports > Log Viewer > Log Viewer under System Logs.
Update access settings of Mail Server to allow access to Cyberoam IP Address. To know how to update settings, refer to the respective documentation of Mail Server vendor.
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