Scanning, Faxing & Copying

Hi all,

I've a customer site with an MFP M426fdw, scanning to email on it used to work. Recently it lost its DNS server settings and stopped working as it was using office 365's SMTP server so it could no llonger find smtp.office365.com.

Upon re-adding the DNS server it could find the SMTP server but still didn't work. I have tried everything I can think of to test this:

What I've done to test this:
-Checked username/password was right (it was, if it's not right we get an error to that effect)
-Tried a new account on Office 365 - Same result
-Tried directsend in office 365 (EG unauthed to a connector on 365 by client IP) - same result
-Tried relaying from an SMTP server we host (both using that server's hostname and IP) - same result - this SMTP server is known working using other MFPs for the same customer at other sites.
-Telnetted from the customer site to smtp.office365.com - this connected fine so the customer site can definitely connect to the office 365 SMTP server.
-Tried port 25 instead of 587 (should work on 365) - complained about using port 25, advised using 587
-Updated the printer's firmware
-Tried with SSL off for office 365 - same error

It appears that the printer does connect to Office 365 but just fails to send the mail, it's not clear why as there are no detailed logs on the printer.

Printer has also been hard rebooted just to make sure thats firmware update took effect.

I suspect it's an SSL issue, the problem is that I've no way of knowing because there's no detailed logging on it and I've no idea how we would fix that, though I have also tried adding the digicert root CA to the printer.

Is there something I'm missing here?

Cheers

Paddy