客户端发送邮件时，如果本机邮箱服务器未接收到命令，则会返回以下错误差错报告(差错报告截图已经出现在上面的图片中)： 未接收到 EHLO——503 Can't receive EHLO\r\n 未接收到 AUTH LOGIN——503 Can't receive AUTH LOGIN\r\n 未接收到 DATA——503 Can't receive DATA\r\n 未接收到 ...