@morrow without logs this will be hard to track down. can you ask your administrator to open up a support case for this?
Today we have made the Zarafa bugtracking system public on http://trac.zarafa.com
This allows users and administrators to find existing issues easily and track if an issue is already merged in a specific version.
At this moment the bug tracking system is only readable.
To report bugs or feature requests, please use the forum. The Zarafa employees will try to reproduce the report issue and create a trac ticket. The link to the ticket will be posted in the forum topic, so all users can track the status of that issue.
Customers with a valid support subscription can report their issues on the Zarafa Support Portal.