SMTP错误：使用其他服务器而不是SMTP时无法连接到SMTP主机

i am working in php. I have wriiten mail functionality using mailer extension of Yii framework with code as-

public function sendsecureEmail($FromEmail,$ToEmail,$Subject,$Message)
    {
        $settings=new Settings();
        $mailer = Yii::createComponent('application.extensions.mailer.EMailer');
        $mailer->IsSMTP();
        $mailer->IsHTML(true);
        $mailer->SMTPAuth = true;
        $mailer->SMTPSecure = 'ssl';
        $mailer->Host =$settings->Host;
        $mailer->Port =$settings->Port;
        $mailer->CharSet = 'UTF-8';
        $mailer->Username =$FromEmail; 
        $mailer->Password =$settings->password;
        $mailer->FromName = 'balaee.com';
    //  $mailer->AddAddress($ToEmail);
        $mailer->Subject = $Subject;
        $mailer->IsHTML(true);
        $mailer->Body=$Message;
        $mailer->AddCC($ToEmail);
    //  $mailer->AddBCC=;
        if($mailer->Send())
        {
            echo "Mail send Successfully.Please you have check mail ";
        }
        else
        {
            echo "Fail to send your message!";
        }
    }

where $setting->$Host="mail.balaee.com",$setting->$Port=25. In php.ini file settings are as-

SMTP = mail.balaee.com
sendmail_from = noreply@balaee.com
smtp_port = 25

When i am trying to send mail its giving me error as-SMTP Error: Could not connect to SMTP host. So what addtional settings i needed to do

I had a similar error. Turned out the DNS settings went blank in centos after the server restarted. After setting them up everything stared working again. Hope it helps.