Thanks Bob, here's a shot of the About screen:
zco.jpg
I've had a look at the link you posted thanks .. but it doesnt seem to be the same issue .. I get this message by just viewing Outlook Today .. no sending of mail involved.
I am a developer in a software house that integrates with Outlook, one of our clients uses this ZCO and server. I am trying to get our software to integrate but find this problem .. strangely enough, clicking Retry or Ignore allows me to proceed, but it is not really something I can implement into our software having this this error pop up constantly.
Regards
Simon