When your local mailserver goes off line ours starts to backup your incoming mail
For clients using SMTP delivery to their server Toucan offer a supporting service called MX Backup. Should your own server, such as your local MS Exchange server, go off line for any reason your incoming mail would be permanently bounced. The MX Backup service will back up this mail to a remote server. This backup server will then retry delivery to your mail server to a fixed schedule of 40 attempts over 7 days. After that time the mail message is rejected. Each message has its own retry schedule. The longer a message remains undeliverable, the less frequently the system tries to send it. The retry schedule is not configurable. We will attempt to deliver mail for up to 7 days while your server is unavailable. After 7 days of failed retry attempts, we will return the message to the sender.
The following table shows the retry schedule for a message that’s undeliverable to a remote recipient until it is ultimately returned to the sender as undeliverable;