I am sure that people will run into this. On the canon image CLASS MF8300C also known as mf8380cdw, it took me some time to figure out how to get scan to email working. Summary is to change the SMTP port to 587 and use your smtp auth set to your Comcast login. The default port 25 won't work and port 465 won't work.
Here is how:
configure the management name/pin.
login as management to the the web UI browser, http://printer-ip/
change the SMTP TX port to 587, find it at System Settings -> Network Settings -> TCP/IP Settings -> Port Number Settings
Enter the info in E-Mails Settings System Settings -> Network Settings -> E-Mail Setting
SMTP Server Addess: smtp.comcast.net
E-Mail Address: your@address
Check Use SMTP Auth
Enter your username: email@example.com
Check Set/Change Password
Password: Your password.
5. Instruction says to power cycle for the new settings, do it.