Share calendar invitation email blocked by Trend

 This article will explain and provide a work around for the known issue of sharing calendar invites being blocked by our third-party security solution (Trend). 

Attempting to add a member of staff to the permissions on any of your calendars will result in an email being sent to that member of staff notifying them that they now have access to the calendar. However this invite includes an .xml file type attachment which is classified as a security risk. Because of this you will receive an email from our security system that looks something like the example below. The calendar invite you sent will be removed from the recipient's mailbox. 

Both the recipient and the sender will receive this. The sender receives this because a copy of the email is put into their 'sent items' and then blocked. 

If you are attempting to share your own main personal calendar, the delegate will still be able to access it using the methods described below. However if it is a secondary calendar you are trying to share this will not work. We would suggest in either case to request a Teams group or Shared Mailbox rather than use a secondary calendar. 

Sharing secondary calendars is now unsupported. In future, you will be required to request a shared mailbox by filling in the following form - New Shared Mailbox

This is because secondary calendars are associated with a staff user account. If the owner is on long term sick leave or leaves the organisation, any future instances of meetings would still remain and not able to be cancelled without an IT administrator. However, if a shared mailbox is used then you have easier access control and management as multiple users with full access that can modify the calendar meetings/events.

Adding a shared calendar in the Outlook application


Adding a shared calendar in Office on the Web