The Continuity Service is meant to detect and react whenever your final destination server stops working, meaning we couldn't connect to it, or there were timeouts during several SMTP transactions.
In certain scenarios, your server could stop working and, instead of not replying to our requests, be actively refusing the connections or messages.
This has been observed, for example, when the hard disk is full. The server is up and running, but unexpectedly couldn't accept a message or connection, actively closing the connection or refusing the message with a 5xx code.
Because of receiving an active rejection from it, our Continuity Service will not detect the outage and will not activate itself, but you may still have the need of enabling the service, to prevent traffic loss.
For these scenarios only, it's possible to trigger the Continuity Service activation manually, by simply specifying a reserved or non-reachable destination server IP address, like 127.0.0.1, or, mostly recommended, 169.254.0.1
This will force the Continuity Service to detect an outage and enable it's re-routing.
Note: Please understand that this configuration should be used only while your destination server is having issues accepting traffic, and that the Continuity Service is meant to be used only as a fallback solution. Using it as a regular email server is against our Terms of Service.
Important: The Continuity Service is an additional service which could lead to additional costs, and it's not enabled by default. Specifying an invalid destination server without having enabled Continuity Service will necessarily lead to inbound traffic loss.