今天在用yii2发送邮件的时候提示
Connection could not be established with host smtp.exmail.qq.com [ #0]
openssl没啥问题，函数权限也有打开了
折腾半天后终于找到解决办法

出问题之前的代码
/common/config/main-local.php中mailer配置

'mailer' => [

'class' => 'yii\swiftmailer\Mailer',

'viewPath' => '@common/mail',

'useFileTransport' => false,//false发送邮件，true只是生成邮件在runtime文件夹下，不发邮件

'transport'=>[

    'class' => 'Swift_SmtpTransport',

    'host' => 'smtp.exmail.qq.com',

    'username' => '这里是公司的邮箱账号',

    'password' => '邮箱密码',

    'port' => '465',

    'encryption' => 'ssl',

],

'messageConfig'=>[

    'charset'=>'UTF-8',

    'from'=>['这里是公司的邮箱账号'=>'Admin']

],

],

控制器中代码

$mail = Yii::$app->mailer->compose();

$mail->setTo('xingdong1117@126.com');

$mail->setSubject('测试邮件');

$mail->setHtmlBody('这里是内容'); //发布可以带html标签的文本

if ($mail->send()) {

    echo "success";

}else {

    echo "failse";

}

解决办法

在/common/config/main-local.php中mailer配置

'transport'=>[

    'class' => 'Swift_SmtpTransport',

    'host' => 'smtp.exmail.qq.com',

    'username' => '这里是公司的邮箱账号',

    'password' => '邮箱密码',

    'port' => '465',

    'encryption' => 'ssl',

    //这里是新加入的内容

    'StreamOptions'=>[

       'ssl'=>[

            'verify_peer' => false, //是否需要验证 SSL 证书

            'verify_peer_name'=>false,//Require verification of peer name.

            'allow_self_signed' => true//是否允许自签名证书

        ],

    ]

],

//更多参数可以查看 http://php.net/manual/zh/context.ssl.php

其实在

在vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer.php 266行代码中

$streamContext = stream_context_create($options);

$this->_stream = @stream_socket_client($host.':'.$this->_params['port'], $errno, $errstr, $timeout, STREAM_CLIENT_CONNECT, $streamContext);

中间加入

$streamContext = stream_context_create($options);

//----

stream_context_set_option($streamContext, 'ssl', 'verify_peer',false);

stream_context_set_option($streamContext, 'ssl', 'verify_peer_name',false);

stream_context_set_option($streamContext, 'ssl', 'allow_self_signed',true);

//-----

$this->_stream = @stream_socket_client($host.':'.$this->_params['port'], $errno, $errstr, $timeout, STREAM_CLIENT_CONNECT, $streamContext);

也得到了解决，不过不如上面的办法

如果在使用phpmailer的时候也出现此问题,可以这样解决

<?php
$mail = new PHPMailer;

//$mail->SMTPDebug = 4;

$mail->isSMTP();

$mail->Host = 'smtp.exmail.qq.com';

$mail->SMTPAuth = true;

$mail->Username = '这里是公司的邮箱账号';

$mail->Password = '邮箱密码';

$mail->SMTPSecure = 'ssl';

$mail->Port = 465;

$mail->SMTPOptions = array(

    'ssl' => array(

        'verify_peer' => false,

        'verify_peer_name'=>false,

        'allow_self_signed' => true

    )

);

$mail->setFrom('这里是公司的邮箱账号','Admin');

$mail->addAddress('xingdong1117@126.com');

$mail->addReplyTo('这里是公司的邮箱账号', 'Admin');

$mail->isHTML(true);

$mail->Subject = '测试邮件';

$mail->Body    = '邮件内容';

if ($mail->send()) {

    echo "success";

}else {

    echo "failse";

}

ps:不知道啥原因导致的这样的情况，我本地是mac环境，没有这样的问题,到了linux服务器上就出现了这样的问题，只有加上这几个参数才可以。等找到真正原因再来写。