I folks, sometimes users of my company have problems sending mails in Outlook. The user create a new message and when he send this mail, appear in the send folder, but don't send. The user push send/receive button whitout success.

Notes. In the messages in the column date appears *unkown*.

To solve this temporally, the user move the message from the send folder to the draft folder, in this moment he push send button and the message go to the send folder with the *correct date* and automatically outlook sends normally.

How can i fix this?

My installation is:
- Zimbra Collaboration Suite / Network Professional Edition (version 5.0.5)
- Zimbra Connector Outlook v 5.0.5 (GA_2199_5.0.2580.5)
- Next friday i will migrate to new Zimbra release (5.0.7) This new release fix this problem?