A number of our users are having an issue that's not immediately noticeable.

Outlook will stop receiving email silently, hours later they may get a phone call from a customer asking if they got their email. The user hits send/receive (which is automated as well) and nothing appears. They need to kill the outlook task and reopen then their messages are delivered via Outlook. If they were running zimbra desktop it's be immediately delivered etc...

I am running zimbra logger on the clients machines but there's such a huge amount of information in it, nothing stands out.

the clients are using ZimbraOlkConnector-5.0.11_GA_2695_5.0.2817.11

Any help?