Laravel - Connection could not be established with host smtp.gmail.com

I've tried all the possible solutions available here in stackoverflow, however nothing... I think the problem is related to the firewall, I can send mail using SMTP gmail on my local level, but not in my server, I get the following message:

Connection could not be established with host smtp.gmail.com [Connection timed out #110]

I've tried the following commands:

ufw allow 587/tcp

iptables -I OUTPUT -p tcp --dport 587 -j DROP

iptables -I OUTPUT -d smtp.gmail.com -p tcp -m tcp --dport 587 -j ACCEPT

iptables -L OUTPUT -n

However not worked...

This is my .env email settings:

MAIL_DRIVER=smtp
MAIL_HOST=smtp.gmail.com
MAIL_PORT=587
MAIL_USERNAME=*****@gmail.com
MAIL_PASSWORD=*****
MAIL_ENCRYPTION=tls

My controller for sending emails:

public function postEmail(PostEmailRequest $request)
{
    if ($request){
        Mail::send('app.pages.contato.email', $request->all(), function($message) use ($request)
        {
            $message->from($request->email , config('settings.website_title'));
            $message->to(config('settings.admin_email'))->subject($request->assunto);
        });

        return redirect('contato');
    }else{
        return redirect('contato')->withErrors($request);
    }
}

And my error:

in StreamBuffer.php line 265
at Swift_Transport_StreamBuffer->_establishSocketConnection() in StreamBuffer.php line 62
at Swift_Transport_StreamBuffer->initialize(array('protocol' => 'tcp', 'host' => 'smtp.gmail.com', 'port' => '587', 'timeout' => '30', 'blocking' => '1', 'tls' => true, 'type' => '1')) in AbstractSmtpTransport.php line 113
at Swift_Transport_AbstractSmtpTransport->start() in Mailer.php line 79
at Swift_Mailer->send(object(Swift_Message), array()) in Mailer.php line 395
at Mailer->sendSwiftMessage(object(Swift_Message)) in Mailer.php line 181
at Mailer->send('app.pages.contato.email', array('_token' => '6Lr1BR5JOW08Z7a3Pr3mEcpTpbeCIppy7cNwKBZ2', 'nome' => 'fdsafdsafds', 'telefone' => '4545454545', 'email' => 'fdsafdsf@fdsfds.com', 'cidade' => 'fdsafdsafsa', 'pais' => 'fdsfsdfdsfds', 'assunto' => 'fdsfdsfds', 'mensagem' => 'gfsd agh fdah gdsjhgd jgds jfgs gfs gfs jg sjgd s'), object(Closure)) in Facade.php line 222
at Facade::__callStatic('send', array('app.pages.contato.email', array('_token' => '6Lr1BR5JOW08Z7a3Pr3mEcpTpbeCIppy7cNwKBZ2', 'nome' => 'fdsafdsafds', 'telefone' => '4545454545', 'email' => 'fdsafdsf@fdsfds.com', 'cidade' => 'fdsafdsafsa', 'pais' => 'fdsfsdfdsfds', 'assunto' => 'fdsfdsfds', 'mensagem' => 'gfsd agh fdah gdsjhgd jgds jfgs gfs gfs jg sjgd s'), object(Closure))) in ContatoController.php line 26
at Mail::send('app.pages.contato.email', array('_token' => '6Lr1BR5JOW08Z7a3Pr3mEcpTpbeCIppy7cNwKBZ2', 'nome' => 'fdsafdsafds', 'telefone' => '4545454545', 'email' => 'fdsafdsf@fdsfds.com', 'cidade' => 'fdsafdsafsa', 'pais' => 'fdsfsdfdsfds', 'assunto' => 'fdsfdsfds', 'mensagem' => 'gfsd agh fdah gdsjhgd jgds jfgs gfs gfs jg sjgd s'), object(Closure)) in ContatoController.php line 26
at ContatoController->postEmail(object(PostEmailRequest))
at call_user_func_array(array(object(ContatoController), 'postEmail'), array(object(PostEmailRequest))) in Controller.php line 256
at Controller->callAction('postEmail', array(object(PostEmailRequest))) in ControllerDispatcher.php line 164
at ControllerDispatcher->call(object(ContatoController), object(Route), 'postEmail') in ControllerDispatcher.php line 112
at ControllerDispatcher->Illuminate\Routing\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 139
at Pipeline->Illuminate\Pipeline\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 103
at Pipeline->then(object(Closure)) in ControllerDispatcher.php line 114
at ControllerDispatcher->callWithinStack(object(ContatoController), object(Route), object(Request), 'postEmail') in ControllerDispatcher.php line 69
at ControllerDispatcher->dispatch(object(Route), object(Request), 'App\Http\Controllers\App\ContatoController', 'postEmail') in Route.php line 203
at Route->runWithCustomDispatcher(object(Request)) in Route.php line 134
at Route->run(object(Request)) in Router.php line 708
at Router->Illuminate\Routing\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 139
at Pipeline->Illuminate\Pipeline\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 103
at Pipeline->then(object(Closure)) in Router.php line 710
at Router->runRouteWithinStack(object(Route), object(Request)) in Router.php line 675
at Router->dispatchToRoute(object(Request)) in Router.php line 635
at Router->dispatch(object(Request)) in Kernel.php line 236
at Kernel->Illuminate\Foundation\Http\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 139
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in Locale.php line 29
at Locale->handle(object(Request), object(Closure))
at call_user_func_array(array(object(Locale), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in VerifyCsrfToken.php line 50
at VerifyCsrfToken->handle(object(Request), object(Closure))
at call_user_func_array(array(object(VerifyCsrfToken), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in ShareErrorsFromSession.php line 49
at ShareErrorsFromSession->handle(object(Request), object(Closure))
at call_user_func_array(array(object(ShareErrorsFromSession), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in StartSession.php line 62
at StartSession->handle(object(Request), object(Closure))
at call_user_func_array(array(object(StartSession), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in AddQueuedCookiesToResponse.php line 37
at AddQueuedCookiesToResponse->handle(object(Request), object(Closure))
at call_user_func_array(array(object(AddQueuedCookiesToResponse), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in EncryptCookies.php line 59
at EncryptCookies->handle(object(Request), object(Closure))
at call_user_func_array(array(object(EncryptCookies), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124
at Pipeline->Illuminate\Pipeline\{closure}(object(Request)) in CheckForMaintenanceMode.php line 44
at CheckForMaintenanceMode->handle(object(Request), object(Closure))
at call_user_func_array(array(object(CheckForMaintenanceMode), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 124
at Pipeline->Illuminate\Pipeline\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 103
at Pipeline->then(object(Closure)) in Kernel.php line 122
at Kernel->sendRequestThroughRouter(object(Request)) in Kernel.php line 87
at Kernel->handle(object(Request)) in index.php line 54

via Chebli Mohamed