Here is an Exchange 2010 server working and we are accessing it via our local Outlook clients (mostly 2010, but also 2007 and 2013). I want to share my calendar with a co-worker (and vice-versa) so that he is able to see when I got other appointments and I can see his. When he tries to send me a share invitation via his Outlook 2010, he gets the error message "Error while preparing to send sharing message." when clicking on "send".
If we both use the OWA, it works fine - I'm able to view his calender and he can view mine.
My question is: How can I debug this error? I'm unable to find the reason behind this.
