Microsoft has released an update to Outlook 2016 that is affecting the operation of our W5 Outlook add-in component. We are currently working on an update to fix this issue. In the meantime there is a workaround that is 100% effective as follows:

In Outlook, go to File > Options > General tab. Under User Interface options, select Optimize for compatibility. Then please close and reopen Outlook.

Keep in mind, this option will only appear after the 1808 update has occurred.