Queue Stops, Newsletters Not Being Sent
It is rare that the queue hangs and stops sending emails in the middle of a delivery, but it’s happened to a few users.
Most common problem: WordPress version is 3.2.1 has a bug that fails to trigger repetitive tasks, like Wysija’s sending of your newsletters.
See the ticket in WordPress’ trac.
Solution: make sure you update your WordPress to the latest version.