Once you have completed all the previous steps and setup the permissions for the guest user, the final step to enable delivery reporting is to add the site URL configuration in the Messente for Salesforce app configuration. Firstly, view your site in the sites list, right-click the site URL and select "Copy Link Address" as shown in the following image
Then return to the Messente for Salesforce application and visit the "Configuration" tab. Press "Edit" under the "Delivery Reporting Configuration" section and paste in the URL you have copied as shown below, and press save. Note the URL should not have a trailing forward slash / character. You should also ensure it specifies the https protocol.
Congratulations! You have setup delivery reporting and any messages sent will not be recorded and status updates captured.