We have an issue with our email campaign, we are able to send the campaign to any email address internally but any email address that is not on the same exchange server that we are using for sending emails fails to send and we end up with the Not delivered message. I am able to send a test message through the settings page to outside email address.
I would like you to perform a quick test using the free tool smtp4dev.
When starting this application, click on 'options' and select tab 'Server'.
Set the port number to the same port number as configured in the advanced settings > Notifications of your project.
Then, delete the files that are listed under ~\App_Data\Sitefinity\Logs and then run the email campaign again.
When this is completed, attach any newly created log files to this case and check if all emails (internal & external) where sniffed by smtp4dev.
Finally, can you clarify where you see the 'not delivered' messages ?
I assume you want me to run this tool on the exchange server. Which is not possible, due to me not having access to this server. When I run it on the web server I get no results. Also there isn't any logs created when sending out a newsletter. The not delivered message is appearing by clicking on the Full report button for the campaign and then clicking on view all subscribers. I can confirm that the message I am seeing is correct as the recipient of this newsletter is letting me know it hasn't come through. The email address for the not delivered is also correct as I am able to send emails to it through outlook.