If you are using the RMail app for Gmail extension and the Send Registered button is not working, please try the steps listed below to resolve the issue.
1. Log out of Gmail.
2. Remove the RMail app for Gmail extension in Chrome.
3. Clear cache in Chrome.
4. Restart Chrome.
5. Add the RMail app for Gmail button.
6. Log into Gmail. The Send Registered button should now be available.
Send some test emails to yourself to verify that everything is functioning - if not, please contact your Customer Success representative.