This article explains how out-of-office email replies are handled when sending out campaigns through your Emma account.

With every email campaign that is sent through Emma, we include a hidden line in your email header that reads something like, This is a bulk email. No need to reply with autoresponders. While most receiving servers pay attention to this command and don't bother delivering out-of-office replies, there are some that don't, so you might still get a handful of those autoresponders.

Most inbox providers should be using that bulk designation to give our mail the specific treatment it requires with regard to autoresponders, mail queues, etc. However, outside of the big inbox providers, there could be a lot of variation on how your emails are treated when a recipient has set an autoresponder. The correct place to send an autoresponder is the return-path address, which will always be @e2ma.net. If we receive one, we dump it into the trash immediately. However, there have been some cases over the years where the receiving server sends the autoresponder to the from address. It's relatively uncommon in comparison, but it certainly does happen.

You may be wondering whether that can be changed. However, we aren't able to customize this on a per-account basis, and since we are a bulk sender, we need to identify ourselves as such.