I recently became IT Manager for a company that uses DotNetNuke to manage its ebusiness website. Users have informed me that for about six months, they have not received notification emails for orders, customer quote requests, or registrations.
I hopped on the site admin and updated the emails to correct person in our office, but quickly realized there was a technical issue with its configuration when I didn't see test emails going through.
I started troubleshooting and in the process I have configured the host and portal administrator accounts, set up the SMTP to our mail server, set up a receive connector in Exchange that allows mail to relay from the ebusiness site, and tried dozens of configurations of user names and passwords as well as anonymous in the SMTP settings.
I've currently got it configured to send through the SMTP server via anonymous. My test email says that it sends successfully, but I actually don't know where to check that.
I am able to send newsletters to my personal gmail account, but not my @workemail.com email address. If it is configured as such, can receive quote notifications to my gmail account. Here is the error I get when trying to send a newsletter email to my work address:
System.Net Error: 0 :  Exception in the SmtpClient#22695746::Send - Mailbox unavailable. The server response was: 5.5.4 <[email protected]>... Mailbox does not exist.
System.Net Error: 0 :  at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
System.Net.Sockets Verbose: 0 :  Socket#40139210::Dispose()
Why would it return "Mailbox does not exist" for my domain email address, but send it successfully to my personal email?
I've gotten quite the education searching through the many DNN forum posts, but seem to be completely stumped and without even a working hypothesis for this one. Let me know if you have any ideas.