Call support, get to 2nd level support and supply the config sheet of the device and the traces and they may be able to help you out. Xerox doesn't do forum support, this is a peer to peer forum (I work at Xerox, but my time here is not official or paid), you have to call.
I had the same problem with a Xerox Workcentre 7120 with latest software 71.24.23.
Then i unchecked the box as in the picture and it works.
Best regards Mattias
That's what I'm looking for, I'll try disabling this and give it a shot and let you know if that's the issue!
I was able to untick that certificate verification you showed me above and I managed to get mail flowing.
I did get another error, but after looking at the packet capture, I had to change the SMTP settings to use local auth. The SMTP configuration page is a little confusing in regard to where it's getting it's credentials from.
Thank you for your suggestions and help!