[mattwad]

This happened to us a couple weeks back. One day I woke up and our domain had been blocked from sending and receiving. We upgraded our account temporarily to get phone chat support, and what happened was they added some filters which unintentionally got triggered by incoming spam. It was completely their fault, and they fixed it in a few minutes, but they couldn't give me much more detail. Not enough for us to leave Mailgun -- everything else has been great -- but it was very concerning, and I am sure many other accounts were affected.