The users can send messages to themselves from the web interface. I didn't have them try from an IMAP client.
Restarting tomcat followed by postqueue -f did not cause the messages to be delivered, however it did cause postfix to attempt delivery. There are currently 12 messages in the deferred queue. Here is a log entry when postfix attempted delivery after the postqueue -f.
Code:
Dec 13 12:15:29 z1 postfix/lmtp[3548]: 04E2929506B6: to=<lisa@xxxx.com>, relay=z1.sfo2.xxx.com[209.xxx.xxx.xxx], delay=61745, status=deferred (host z1.sfo2.xxx.com[209.xxx.xxx.xxx] said: 451 4.0.0 Temporary message delivery failure try again (in reply to end of DATA command))