Messages are not delivered, they are queued. Admin saw all messages in View SMS queue.
Usually, before 0.9.9.2, this is the case of daemon scripts issue, they are not running or running improperly such as wrong path configured in /etc/default/playsms.
But since I introduced SMS scheduler, a way to schedule delivery of submitted SMS through Send SMS page or webservices, one more issue unfortunately has emerged. It’s the timezone settings, PHP simply cannot determine exact timezone used in the script. The result is every SMS submitted NOW will end up being scheduled for next hour depend on the timezone that actually guessed by PHP.
A discussion in the group shows an example of user experiencing this issue.
So, if you experienced an issue like the first paragraph in this article, and you already make sure that all daemon scripts are running and well configured, then its time to check the timezone settings.