Action Mailer在尝试发送电子邮件时会中断应用程序

Looking for help with the action mailer in rails. I'm using Rails 3.2 and devise for authentication. I followed the railscasts to get started on using the action mailer so I'm setting up the action mailer for my first time and ran into some issues. I've set devise's registration controller to send out an email when registering. What's happening is the application is breaking when it hits that line of code to send out an email. I'm including my logs, action mailer, etc below for help....Thanks for the helpLooking for help with the action mailer in rail