Devlogs are sent to your followers via an email digest if their account settings have that enabled.
The digest groups devlog posts from other people they follow, so it does not go out immediately after a devlog is published. The digest emails go out at most once per day. You will have to wait at most 24 hours before you can confirm if the email was sent or not, and I see that your devlog was just posted 4 hours ago. Hope that explains.