Server Hang-Ups and Long Loading Errors When Sending Emails Using PrestaShop's Standard Sendmail Method

Introduction

One common issue that PrestaShop store owners face is server hang-ups or long loading times when sending emails using the standard sendmail method. In this article, we will explore the reasons behind this problem and provide a solution to avoid email sending errors.

What is Sendmail?

Sendmail is a mail transfer agent (MTA) used to route and deliver email messages between servers. It is one of the oldest and most widely used mail agents, supporting various protocols and standards for email transmission. PrestaShop uses sendmail to send emails if no other method, such as SMTP, is configured.

Why Do Errors Occur When Using Sendmail with the -bs Option?

By default, PrestaShop uses the command /usr/sbin/sendmail -bs to send emails. Let's break down what this means.

• -bs — This option instructs sendmail to operate in SMTP mode, allowing it to interact directly with the SMTP server. However, this mode can be less stable and cause issues, especially on servers with limited resources or incorrect configurations.

The main reasons for errors when using the -bs mode include:

1. High Server Load: The -bs mode requires significant server resources to process each email, leading to long loading times and hang-ups.
2. Incorrect Configuration: Some servers may not be correctly configured to work with the -bs mode, resulting in email sending errors.

The Solution

To avoid hang-ups and errors when sending emails, you can change the sendmail execution parameter from -bs to -t. Here’s how to do it.

1. Locate the sendmail configuration file in PrestaShop: It is usually located at /vendor/swiftmailer/swiftmailer/lib/classes/Swift/SendmailTransport.php.

2. Change the execution parameter: In the SendmailTransport.php file, find the following line:

   public function __construct($command = '/usr/sbin/sendmail -bs')

   and replace it with:

   public function __construct($command = '/usr/sbin/sendmail -t')

   The -t option instructs sendmail to read the email recipients from the headers of the email. This mode is more standard and less resource-intensive.

3. Restart the server: After making these changes, restart the server to apply the new settings.

Testing Email Sending

After changing the sendmail parameters, verify the email sending functionality:

1. Go to the PrestaShop admin panel.
2. Send a test email through the email sending interface.
3. Ensure the email sends without errors or delays.

Conclusion

Using the standard sendmail method with the -bs option can lead to server hang-ups and errors. Switching to the -t option can help avoid these issues, improving the stability and performance of your online store. We hope this article helps you resolve the issue and ensures the smooth operation of your PrestaShop store.