You beat me to it, I was just going to add that to my post.
However, I think I have found the problem, but not necessarily the answer. SSH into your server and go to
/opt/twig/config and look in config.inc.php3
you will find the following line:
$config["fromdomain"] = "foo.com"; //This is where mail is sent from
I changed this to my domain and all works now !!
Hope this helps.
EDIT: Did this work as well for you, as it seems to have done for me ?
Please note I do NOT know if this breaks anything else, but looks good so far.
Mudra