ChangeSender consists of two components that must both be installed:
- Server component — installed on the Exchange server
- Client component (Outlook add-in) — installed on each user's PC
The Outlook add-in alone is not sufficient. If only the client is installed, ChangeSender appears to work but cannot change the sender address because there is no server component to handle the Exchange-side processing.
Install the server component on your Exchange server and the problem will be resolved. See the installation guide for step-by-step instructions.