proc_open error with the Contact Form

Question

I get the following error upon submit of the contact form (Pixel and Tonic's version).

proc_open() has been disabled for security reasons

Using Craft 3.0.5 and Contact Form 2.1.1. Email is being sent by Sendmail

Client's website host are not willing to enable proc_open. Is anyone aware of a simple way around this?

Here's the Stack Trace:

yii\base\ErrorException: proc_open() has been disabled for security reasons in /home/blahblah/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer.php:296
Stack trace:
#0 /home/blahblah/vendor/craftcms/cms/src/web/ErrorHandler.php(84): yii\base\ErrorHandler->handleError(2, 'proc_open() has...', '/home/blahblah/...', 296)
#1 [internal function]: craft\web\ErrorHandler->handleError(2, 'proc_open() has...', '/home/blahblah/...', 296, Array)
#2 /home/blahblah/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer.php(296): proc_open('/usr/sbin/sendm...', Array, Array)
#3 /home/blahblah/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/StreamBuffer.php(58): Swift_Transport_StreamBuffer->establishProcessConnection()
#4 /home/blahblah/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(126): Swift_Transport_StreamBuffer->initialize(Array)
#5 /home/blahblah/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/SendmailTransport.php(52): Swift_Transport_AbstractSmtpTransport->start()
#6 /home/blahblah/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Mailer.php(67): Swift_Transport_SendmailTransport->start()
#7 /home/blahblah/vendor/yiisoft/yii2-swiftmailer/src/Mailer.php(151): Swift_Mailer->send(Object(Swift_Message))
#8 /home/blahblah/vendor/yiisoft/yii2/mail/BaseMailer.php(263): yii\swiftmailer\Mailer->sendMessage(Object(craft\mail\Message))
#9 /home/blahblah/vendor/craftcms/cms/src/mail/Mailer.php(159): yii\mail\BaseMailer->send(Object(craft\mail\Message))
#10 /home/blahblah/vendor/craftcms/contact-form/src/Mailer.php(100): craft\mail\Mailer->send(Object(craft\mail\Message))
#11 /home/blahblah/vendor/craftcms/contact-form/src/controllers/SendController.php(51): craft\contactform\Mailer->send(Object(craft\contactform\models\Submission))
#12 [internal function]: craft\contactform\controllers\SendController->actionIndex()
#13 /home/blahblah/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array(Array, Array)
#14 /home/blahblah/vendor/yiisoft/yii2/base/Controller.php(157): yii\base\InlineAction->runWithParams(Array)
#15 /home/blahblah/vendor/craftcms/cms/src/web/Controller.php(76): yii\base\Controller->runAction('', Array)
#16 /home/blahblah/vendor/yiisoft/yii2/base/Module.php(528): craft\web\Controller->runAction('', Array)
#17 /home/blahblah/vendor/craftcms/cms/src/web/Application.php(272): yii\base\Module->runAction('contact-form/se...', Array)
#18 /home/blahblah/vendor/craftcms/cms/src/web/Application.php(520): craft\web\Application->runAction('contact-form/se...', Array)
#19 /home/blahblah/vendor/craftcms/cms/src/web/Application.php(256): craft\web\Application->_processActionRequest(Object(craft\web\Request))
#20 /home/blahblah/vendor/yiisoft/yii2/base/Application.php(386): craft\web\Application->handleRequest(Object(craft\web\Request))
#21 /home/blahblah/web/index.php(21): yii\base\Application->run()
#22 {main}

Answer 1

I'm about 99% sure that if you swap from using sendmail to SMTP, or almost any of the other mail transports in the "Mail Adaptors" category in the Craft 3 Plugin Store (SES, Postmark, Mandrill), they won't end up going through proc_open.