Hi, reporting this as a bug. I've opened two threads in the community discussion and they both just died with no response. The first was answered, but when I followed up, no response from SmarterTools.
First link is original thread, second is my attempt to resurrect the topic and get someone's attention at SmarterTools.
Basically, smartermail isn't allowing anonymous relay according to the docs and response from ST. I've followed the instructions as suggested and it still doesn't allow relay.