We've been using the "Email Users" part of the community bubbles plugin for occasional announcements. We use this on a non-public instance of confluence with about a thousand users total. When we try to send an announcement all of our users, we see an error in the web page after submitting the email form.
The error is a "Bad Gateway" message, which, I suppose, is typical of tomcat not responding to requests proxied by apache. As far as I can tell, the emails seem to go out to all recipients despite this error. When we send messages to a smaller group, say fewer than 200, we don't see this error.
Our server is an 8-core xeon system with gobs of RAM (28GB on the system), and the confluence JVM has:
Maximum Heap Size 1820 MB
Total Allocated Memory 881 MB
Used Memory 709 MB
Free Allocated Memory 172 MB
Total Free Memory 1111 MB
Maximum PermGen 256 MB
Used PermGen 168 MB
Has anyone else seen this problem with the Email users tool?