Is there a way to set up Ignition to send out email alerts from a backup email server in the event that a primary email server is down?
It is not built into Ignition to accomplish this. However, you may be able to accomplish it using the distribution group email profile. That profile allows you to validate alarms against an expression. If you can somehow detect that your primary email server is down you can use one profile for when it is up and a second profile for when it is down. They would have different SMTP servers.
This is a good feature request. I will put a ticket in.
The way we do it here -
I setup a cname alias to our mail server. If my primary server goes down I can make a quick DNS change to the backup server.