I have a couple of people who have subscribed to one of my lists, but have never confirmed their email and thus are in limbo as far as getting and sending messages on the list.? Both have "" addresses.?
That might relate to a general problem delivering to hotmail recently. See beta . I'm not sure if there's anything you can do but try periodically until this gets fixed.
Is hotmail known for putting these kind of messages into spam?
Hotmail has been known to have deliverability problems with mail from Groups.io in the past. It wouldn't surprise me if? they sometimes
deliver them to the user's spam folder
rather than outright bounce the messages, as currently.