Hacker News Reader

SES works for me. Do any of the cloud providers even allow SMTP from their IPs?

All of them?

At least all those I've ever used or looked into do.

IP ranges used for VMs are often problematic. I wouldn’t recommmend them for outgoing mail. See: https://news.ycombinator.com/item?id=7634890

Perhaps I misunderstood. Since he/she mentioned "SES" I thought the "cloud providers" were SendGrid, etc.