Sorry for the delayed response. Some emails created or forwarded by Outlook 2016 32 Bit with Scalix Outlook connector (latest Version 12.7) can not be read by the recipient. The email body (message text) is blank and there is an attachment with the Extension ".dat". This attachment is readable with MS Word as it seems to be in RTF format.
For testing purposes I installed Outlook 2013 with Scalix connector on another machine and created a Outlook profile for the user reporting this error (the user forwarded an incoming mail to another recipient). So I forwarded this email again with the result that all is working correct. A forwarding test with this email in Outlook 2016 on the users machine reporting the error (Outlook 2016) resulted in the above described error. There is no setting set for sending in RTF-format (Outlook options or recipient specific options).
Could you contact me (email) so I can send you this specific email (confidential) that I saved in Outlook message format?