Liberum has stopped sending emails

[Zourous]

Our Liberum helpdesk (uses CDONTS) has all of a sudden stopped sending notification emails. To our knowledge nothing has changed. Liberum is on one server and uses smtp to relay to our exchange 2007 server in the same domain. I think I've ruled Liberum out, as we have two helpdesks and both have stopped sending emails. I've also tried dropping a test email into the IIS pickup folder and the mail always ends up in the Badmail folder with the rest of the Liberum stuff. The error message on the log files says:

 

smtp;550 5.7.1 Unable to relay for (email address)

 

I've checked exchange and the receive connectors are setup to accept relaying from all our internal servers so all seems fine there.

 

Anyone have any clues to how this has suddenly stopped?

[Zourous]

Have answered my own question. The smarthost setting for our mail server was missing on IIS \ SMTP Virtual server \ Delivery \ Advanced. God knows why it disappeared or even if it was there in the first place, but the email notifications are all working again and that is good enough for me. Hopefully this thread will help someone else out one day if not myself if the same happens again.