启动插件设置好邮箱信息之后，点击测试邮箱报错Attempt to assign property "from" on null

[qingyunnest]

Attempt to assign property "from" on null
Error: Attempt to assign property "from" on null in /app/usr/plugins/CommentToMail/Action.php:341
Stack trace:
#0 /app/usr/plugins/CommentToMail/Action.php(405): CommentToMail_Action->testMail()
#1 /app/var/Widget/Action.php(71): CommentToMail_Action->action()
#2 /app/var/Typecho/Widget.php(155): Widget\Action->execute()
#3 /app/var/Typecho/Router.php(96): Typecho\Widget::widget('\Widget\Action', NULL, Array)
#4 /app/index.php(23): Typecho\Router::dispatch()
#5 {main}