Cannot send email using Laravel 5

I wrote this code a couple of months ago. I used to be able to send email with the following configuration. But suddenly today, I am getting the following error.

Swift_TransportException in StreamBuffer.php line 265:

Connection could not be established with host localhost [Connection timed out #110]

This is the configuration from which I was able to send emails. Please help me. I am really confused?

'driver' => 'smtp',

'host' => 'localhost',

'port' => 587,

'from' => ['address' => "test@xxx.com", 'name' => "test"],

'encryption' => 'tls',

'username' => 'test@xxx.com',

'password' => '*********',

'sendmail' => '/usr/sbin/sendmail -bs',

'pretend' => false,

via Chebli Mohamed