I just created a newsletter and sent it out. The newsletter was sent to rank 1 and higher. (I'm rank 0, default rank name is guild leader.) It said it queued 4 emails which sounds correct (2 rank 1s, 1 rank 0, and dkpsystem.com admin account). I did not receive the newsletter, but the rank 1 people did.
A rank 1 person create a newsletter that was sent to everyone. Both the rank 1 who sent it and myself received it.
That seems a little strange. I'd expect to receive the first one as well. Since the second one came through, I'm confident a spam filter is not getting in the way.