Mysterious error message using Swiftmailer

Hi guys,using following static cofiguration will cause exception like this.
Swift_TransportException: Failed to authenticate on SMTP server with username "thomas.kipp@eisvogel-online-software.de" using 3 possible authenticators in

Using mail client will send mail without any problems,so following parameter basically are correct

  'mailer' => [
            'class' => 'yii\swiftmailer\Mailer',
            'viewPath' => '@common/mail',
            'useFileTransport' => false, //set this property to true to send mails to mail emulator. Set this property to false to send real mails.              
            'transport' => [
                'class' => 'Swift_SmtpTransport',
                'host' => 'smtp.strato.de',
                'username' => 'thomas.kipp@eisvogel-online-software.de',
                'password' => 'top secret',
                'port' => '587',
                'encryption' => 'tls',
            ],
        ],

What is wrong with this configuration? Following configuration:

     'mailer' => [
            'class' => 'yii\swiftmailer\Mailer',
            'viewPath' => '@common/mail',
            'useFileTransport' => false, //set this property to true to send mails to mail emulator. Set this property to false to send real mails.              
            'transport' => [
                'class' => 'Swift_SmtpTransport',
                'host' => 'smtp.gmail.com',
                'username' => 'tklustig.thomas@gmail.com',
                'password' => 'top secret',
                'port' => '587',
                'encryption' => 'tls',
            ],
        ],

will throw out error like this:
Swift_TransportException: Connection could not be established with host smtp.gmail.com [Connection timed out #145] in

Same thing with gmx. I am not able any more, sending mails using Swiftmailer. What could I do?