Add a secondary mail server for mail sending
At times we have to reboot our email server and during this time AbleCommerce will error and fail to send order notifications to customers, vendors, etc. I'm actually surprised we've come this long without this implemented but we need to be able to configure a primary and secondary mail server. If the mail send fails on the primary then AbleCommerce should retry on the secondary mail server.
Chip Wimbauer commented
I think you may be able to do this with your DNS entry. As I recall in DNS you can set a priority and if the higher priority server doesn't respond, the second in the list is tried.