Hey Kathryn -- That's not good. As far as I know, the subscribers bounced after unsuccessful attempts of ConvertKit to reach their email server. They do this to maintain the good health and deliverability of our list. I would suggest reaching out to their deliverability so that they can check what's happening with the bounces. You can reach them here: https://convertkit.com/support20

Robert
Free Diver | Adventurer