At first with authentication off, connection test in command center was OK but got 3101 when trying to send email. (printing and smb scanning OK) When auth. was turned on test in comm center 3101. They have good IT and now with auth. on, connection test in command center OK, but when trying to actually send email I get 3101. They have their own smtp server, email size limit set to 0, using valid email address, email has subject populated. Any and all ideas please thanks.

Depends a whole lot on their mail server. They may need to allow that ip to send mail through their server. Newer versions of exchange force you to turn authentication off, (or you get 3101 error) and then you can only send emails in-house. Hope this helps.

Ok I'm done !!! Honestly not sure exact detail to get it going. But, the customer had authentication off. All I did was turn it back on (with settings already there) and set timeout to 90