We've been running our current exchange 2010 server for about 9 months now and every thing has been working fine. But, today all of our multi-function printers that are set up to scan to email are no longer able to send emails.
Nothing has changed on the mail server or the scanners. It just stopped working for no obvious reason. Our mailserver still works as expected. We can send emails internally and externally. Outlook and OWA work properly. It's just the scanners that give me the error "Transmit/Receive Error (0x3101)".
They are sending emails without authentication. There is a receive connector that allows their IP addresses to send emails without authentication.
I figured that I would try and send an email through the exchange server with telnet on port 25. But when I try it just says Connection timed out as soon as I type EHLO or HELO.
Any ideas about what's going on?