Although I don't use it myself because I can't stand Outlook, many of our employees want to use Outlook, (crazy I know)!

We are now on Version 4.5.1_GA_660.RHEL4 and using the Outlook connector from it, (4.5.0_GA_611_4.5.115.msi).

I only actually launched Zimbra into live use on our Network a couple of weeks ago and am generally very happy with it.
I installed the connector on the relevant PC's, all using either Win2K or WinXP with Office 2003 and allowed each to synchronise with the user's profile on Zimbra. This worked fine but after a day or two some of the users were not receiving the latest mail from their Zimbra profiles, it was as though Outlook was no longer looking at Zimbra or had the wrong details.
If I go into 'Email Options' within Outlook and have a look at the details with which we are connecting to the Zimbra Server I get an error on clicking on 'OK' whether I change anything or not (an unknown error has occurred, error code: 0x80040119). I use the actual IP address of the Zimbra server as opposed to the DNS name for the 'Server Name' box and just the Users name in the 'Email Address' box (i.e russ instead of russ@domain.com). This seems to work fine on most of our PC's. This error occurs on both non-synchronising machines as well as ones which have a working Zimbra connector installed.

Does any of this sound familiar to anyone else?
I don't know if it is just Outlook itself which is at fault or our Network somehow.

After the sychronising fault originally occurred, everything has been running smoothly, my Outlook still crashes at least once a day but I put this down to my PC and Outlook just being extremely buggy.

I would probably have just forgotten about the error in fact but it hadn't happened again this morning on one PC. This was synchronising fine up until last night, the one thing I changed was to test External Authentication through the Zimbra Admin UI with a mind to forcing Active Directory passwords on our Zimbra users. This works fine by the way but has this in some way caused the fault? Could this have caused Outlook to lose the connection to Zimbra? If so, is there a way of reconnecting to it without uninstalling and reinstalling the Connector itself and having to synchronise Outlook from scratch again?

Sorry this is so long but wanted to give all the details!

Thanks for any help

Russ