First check that you have the extension installed. Click the grey puzzle icon top right next to the address bar to open the extension menu then click on Manage Extensions. If: You can't see it in the list, install it from the Chrome Web Store You see it in the list, then make sure it's enabled by turning the toggle on Finally, reload the Gmail page and the button should now appear. If you still can't see the Send Later button, then another extension might be conflicting with Recurring Emails for Gmail. Kindly take a screenshot of the extension page opened above and send it to support@recurring-emails-for-gmail.com