If the Outlook Add-In is no longer visible when composing a new message then there could be a number of different reasons.
Note: Actions listed and screenshots shown apply to MS Outlook 2013 & 2016. Steps for earlier versions of MS Outlook may vary slightly.
Problem
The Outlook Add-in no longer appears when composing a new message in either Outlook 2013 or 2016 when it was correctly appearing before.
Resolution
Follow these instructions first and then reference further instructions below as directed
1. In Outlook click the File menu item
2. Click Options
3. Click Add-Ins
In the Add-Ins preview pane, locate Delivery Trust Outlook Add-in.
If the add-in is located in the Inactive Application Add-ins section, follow steps in the Inactive Add-in section.
If the add-in is Located in the Disabled Application Add-ins section, follow the steps in the Disabled Add-in section.
If the add-in doesn’t exist at all, follow the instructions to perform a fresh installation of the add-in documented here.
INACTIVE ADD-IN
1. Click Go… (bottom of the Add-Ins windows)
2. Check the box next to the Delivery Trust Outlook Add-in listing and click OK.
If prompted to register the Add-in, follow the on-screen instructions to do so.
DISABLED ADD-IN
1. Change the Manage: option to Disabled Items and click Go…
2. In the Disabled Items window select the Delivery Trust Add-in and click Enable.
3. Click Close to exit the Disabled Items window.
4. Change the Manage: option to COM Add-ins and click Go…
5. Check the box next to the Delivery Trust Outlook Add-in listing and click OK.
If prompted to register the Add-in, follow the on-screen instructions to do so.
This completes the actions to re-activate your Delivery Trust Add-in for MS Outlook.
You should now be able to resume sending secure email using the Delivery Trust Microsoft Outlook Add-in.