SSL error while sending mail using SwiftMailer on DigitalOcean droplet. How to debug?

0

I don’t know how to go about debugging this. Any help would be great!

I am using Laravel 4.2 (I know it’s high time I upgrade). I am sending mail using Gmail SMTP. I am able to send mail on local environment without issue, but on the production server it is throwing the following error:

[2020-11-20 15:55:52] production.ERROR: ErrorException: stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages:
error:14161044:SSL routines:state_machine:internal error in /var/www/domain.com/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer.php:94
Stack trace:
#0 [internal function]: Illuminate\Exception\Handler->handleError(2, 'stream_socket_e...', '/var/www/domain...', 94, Array)
#1 /var/www/domain.com/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer.php(94): stream_socket_enable_crypto(Resource id #10, true, 9)
#2 /var/www/domain.com/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/EsmtpTransport.php(313): Swift_Transport_StreamBuffer->startTLS()
#3 /var/www/domain.com/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(118): Swift_Transport_EsmtpTransport->_doHeloCommand()
#4 /var/www/domain.com/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mailer.php(79): Swift_Transport_AbstractSmtpTransport->start()
#5 /var/www/domain.com/vendor/laravel/framework/src/Illuminate/Mail/Mailer.php(307): Swift_Mailer->send(Object(Swift_Message), Array)
#6 /var/www/domain.com/vendor/laravel/framework/src/Illuminate/Mail/Mailer.php(134): Illuminate\Mail\Mailer->sendSwiftMessage(Object(Swift_Message)) #7 /var/www/domain.com/bootstrap/compiled.php(3180): Illuminate\Mail\Mailer->send('emails.bulk-ord...', Array, Object(Closure))
#8 /var/www/domain.com/app/libraries/functions/sendMail.php(34): Illuminate\Support\Facades\Facade::__callStatic('send', Array)
#9 /var/www/domain.com/app/controllers/BulkOrderController.php(70): App\Libraries\Functions\sendMail('emails.bulk-ord...', Array, Array, 1)
#10 [internal function]: BulkOrderController->checkout()
#11 /var/www/domain.com/vendor/laravel/framework/src/Illuminate/Routing/Controller.php(231): call_user_func_array(Array, Array)
#12 /var/www/domain.com/bootstrap/compiled.php(5437): Illuminate\Routing\Controller->callAction('checkout', Array)
#13 /var/www/domain.com/bootstrap/compiled.php(5425): Illuminate\Routing\ControllerDispatcher->call(Object(BulkOrderController), Object(Illuminate\Routing\Route), 'checkout')
#14 /var/www/domain.com/bootstrap/compiled.php(4657): Illuminate\Routing\ControllerDispatcher->dispatch(Object(Illuminate\Routing\Route), Object(Illuminate\Http\Request), 'BulkOrderContro...', 'checkout')
#15 [internal function]: Illuminate\Routing\Router->Illuminate\Routing\{closure}()
#16 /var/www/domain.com/bootstrap/compiled.php(4984): call_user_func_array(Object(Closure), Array)
#17 /var/www/domain.com/bootstrap/compiled.php(4682): Illuminate\Routing\Route->run(Object(Illuminate\Http\Request))
#18 /var/www/domain.com/bootstrap/compiled.php(4670): Illuminate\Routing\Router->dispatchToRoute(Object(Illuminate\Http\Request))
#19 /var/www/domain.com/bootstrap/compiled.php(706): Illuminate\Routing\Router->dispatch(Object(Illuminate\Http\Request))
#20 /var/www/domain.com/bootstrap/compiled.php(687): Illuminate\Foundation\Application->dispatch(Object(Illuminate\Http\Request))
#21 /var/www/domain.com/bootstrap/compiled.php(7311): Illuminate\Foundation\Application->handle(Object(Illuminate\Http\Request), 1, true)
#22 /var/www/domain.com/bootstrap/compiled.php(7908): Illuminate\Session\Middleware->handle(Object(Illuminate\Http\Request), 1, true)
#23 /var/www/domain.com/bootstrap/compiled.php(7855): Illuminate\Cookie\Queue->handle(Object(Illuminate\Http\Request), 1, true)
#24 /var/www/domain.com/bootstrap/compiled.php(10990): Illuminate\Cookie\Guard->handle(Object(Illuminate\Http\Request), 1, true)
#25 /var/www/domain.com/bootstrap/compiled.php(648): Stack\StackedHttpKernel->handle(Object(Illuminate\Http\Request))
#26 /var/www/domain.com/public/index.php(49): Illuminate\Foundation\Application->run()

The code is hosted on a DigitalOcean droplet (Ubuntu 20.04).

Contents of app/config/mail.php:

<?php

return array(
    'driver' => 'smtp',
    'host' => 'smtp.gmail.com',
    'port' => 587,
    'from' => array('address' => 'contact@domain.com', 'name' => 'Company Name'),
    'encryption' => 'tls',
    'username' => 'GmailUserName',
    'password' => 'GmailPassword',
    'sendmail' => '/usr/sbin/sendmail -bs',
    'pretend' => false,
);