Laravel collective SSH put method not working

I am trying to upload contents from one server to another using LaravelCollective SSH https://laravelcollective.com/docs/5.5/remote

I have successfully installed the package and added it in the Laravel providers and generated its config file successfully. The config/remote.php looks like:

    'connections' => [
        'remoteDropbox' => [
            'host' => '111.222.33.444:222', //ip and port number
            'username' => 'user',
            'password' => 'abc123',
            'key' => '',
            'keytext' => '',
            'keyphrase' => '',
            'agent' => '',
            'timeout' => 300,
        ],
    ],

Also I can able to connect to remote server and execute some code to list contents from server using SSH::into('remoteDropbox')->run() method.

But I cannot able to put content to remote server. I tried:

SSH::into('remoteDropbox')->put(
    "/var/www/html/local-server/public/toExport/test.zip", //localfile
    "/var/www/html/dropbox/public/inbox" //remote path
);

Could anyone tell me why the content is not uploading to remote server. My Laravel version is 5.5 and Laravelcollective/remote is 5.5

via Chebli Mohamed