首先判断sendmail是否安装？

直接yum install sendmail，没有安装会安装好。
接着启动/etc/init.d/sendmail
检测一下 /etc/init.d/sendmail status

修改 vi /usr/local/php/etc/php.ini PHP的配置文件
输入/sendmail_path 查找到sendmail_path 修改为 sendmail_path = /usr/sbin/sendmail -t –i

接着重启php-fpm
/etc/init.d/php-fpm restart

再测试，OK