What can be wrong with Magento not sending emails via SMTP?

Question

SMTP

Hello. I've been facing a problem for a long time that I still can't find a solution to.
Magento had the SMTP Pro Email add-on installed and it worked without issue. One fine day, users were unable to receive a confirmation email. The most interesting thing is that no one touched the site, except for adding a product. Well, system emails do not go away, although the verification email comes without problems, but the plugin throws an error:

SMTP Pro Self Test Results
Sending test email to your contact form address: [email protected] from: [email protected]
Test email was sent successfully.
Default templates exist.
Email communications are enabled.
Required database tables exist.
Testing failed, please review the reported problems and if you need further help visit the support page or contact me via [email protected] for support.

The plugin author has a similar question on the support page, but he does not know the answer to it.
On magento.stackexchange.com , people are also silent.
I tried all similar plugins, the result is the same. In other words, it's not about him.
Checked with localhost, the result is the same. Not in the server (at least not obviously) business.
I installed a clean 1.9.1 and uploaded plugins and a working database to it - it worked on localhost! But as an option it is not suitable, since transferring all the settings and filing the theme is simply not really problematic.
If you have any idea why, please let me know! Thank you!
Website

Answer 1

Mail worked after removing the module

app/etc/modules/Rugento_Payment.xml
app/etc/modules/Rugento_Invoicebank.xml

I'm talking to developers.
Thanks for the help!

Answer 2

Oh, there is a debug in the plugin that will solve all your problems.

Answer 3

You need to add the lines to the file Aschroder_SMTPPro_Model_Email_Template

$mail = $this->getMail();
        
        /*************************Добавить ***********************************/
        try {
            if(isset($variables['order'])) {
                $instance = $variables['order']->getPayment()->getMethodInstance();
                if($instance->getCheckOrder($variables['order'])) {
                    $attachments = $instance->getNewOrderAttachment(); //получаем вложения из метода оплаты

                    if(is_array($attachments)) {
                        foreach ($attachments as $attachment) {
                            if(!$attachment instanceof Zend_Mime_Part) continue; // если не наш метод, не загружаем
                            $mail->addAttachment($attachment);
                        }
                    }
                }
            }
        } catch (Exception $e) {
            Mage::logException($e);
        }
        /**************************END добавить*******************************/

        if ($returnPathEmail !== null) {

and comment out the block in the app\code\local\Rugento\Invoicebank\etc\config.xml file:

<core>
<rewrite>
<email_template>Rugento_Invoicebank_Model_Core_Email_Template</email_template>
</rewrite>
</core>