We are in the process of setting up a new CF 11 server. We are getting this error "error javax.mail.AuthenticationFailedException: 451 4.7.0" in the logs when we use cfmail that has been working for years on a CF9 server. Also the mail is in the Undelivered folder. We can drag to Spool, but it just comes back.
We do use MS Exchange 2013 and we have added our CF11 servers IP in the Frontend connector that we use to relay mail to allow email from our CF server.
Did something change with how ColdFusion processes email from CF9 to CF11?
Our current cfmail parameters.
I am sorry to say I have this same issue. We are still running CF10 and have *never* been able to connect to Exchange with CFMail since upgrading from CF9 no matter what we tried. Our solution has been to use the 'mail.jar' file from CF9. Simply replace this in your CF install directory and restart CF. It works flawlessly on our CF10 install. Sorry, haven't tried it on CF11 yet.
Oh, and keep that CF9 mail.jar file handy, because many of the security updates that you install for CF will restore the original mail.jar file. We simply copy back in the CF9 JAR.
Wish I had a better solution for you.