Fatal Error Resending Failed Email

Resolved Matt Pramschufer
(@mattpramschufer)

11 months, 3 weeks ago

Hello,
I am getting a fatal error when resending a failed email.

[16-Jun-2025 12:10:30] WARNING: [pool www] child 27513 said into stderr: “NOTICE: PHP message: PHP Fatal error: Uncaught TypeError: preg_match(): Argument #2 ($subject) must be of type string, array given in /var/www/domain.com/wp-includes/PHPMailer/PHPMailer.php:1877”
[16-Jun-2025 12:10:30] WARNING: [pool www] child 27513 said into stderr: “Stack trace:”
[16-Jun-2025 12:10:30] WARNING: [pool www] child 27513 said into stderr: “#0 /var/www/domain.com/wp-includes/PHPMailer/PHPMailer.php(1877): preg_match(‘#^[a-z][a-z\d+….’, Array)”
[16-Jun-2025 12:10:30] WARNING: [pool www] child 27513 said into stderr: “#1 /var/www/domain.com/wp-includes/PHPMailer/PHPMailer.php(1889): PHPMailer\PHPMailer\PHPMailer::isPermittedPath(Array)”
[16-Jun-2025 12:10:30] WARNING: [pool www] child 27513 said into stderr: “#2 /var/www/domain.com/wp-includes/PHPMailer/PHPMailer.php(3267): PHPMailer\PHPMailer\PHPMailer::fileIsAccessible(Array)”
[16-Jun-2025 12:10:30] WARNING: [pool www] child 27513 said into stderr: “#3 /var/www/domain.com/wp-content/plugins/fluent-smtp/app/Functions/helpers.php(579): PHPMailer\PHPMailer\PHPMailer->addAttachment(Array, ”)”
[16-Jun-2025 12:10:30] WARNING: [pool www] child 27513 said into stderr: “#4 /var/www/domain.com/wp-content/plugins/fluent-smtp/fluent-smtp.php(49): fluentMailSend(Array, ‘Do Downtow…’, ‘First Name: Nic…’, Array, Array)”
[16-Jun-2025 12:10:30] WARNING: [pool www] child 27513 said into stderr: “#5 /var/www/domain.com/wp-content/plugins/fluent-smtp/app/Models/Logger.php(384): wp_mail(Array, ‘Do Down…”

https://pramadillo.s3.us-east-1.amazonaws.com/email-preview.png

Thank you in advance!

Viewing 2 replies - 1 through 2 (of 2 total)

Plugin Support Ibrahim Sharif
(@ibrahimsharif)

11 months, 3 weeks ago

Hello @mattpramschufer,

Thanks for reaching out to us regarding the fatal error you’re encountering while resending failed emails. I’ve reviewed the error log you provided, and it appears the issue stems from the preg_match() function within the PHPMailer library receiving an array instead of a string for the subject when attempting to add an attachment.

Based on the stack trace, it seems FluentSMTP is involved in this process. To help me further diagnose the problem, could you please confirm the PHP version your server is currently running?

As a first step, I highly recommend trying PHP version 8.1. In many cases, updating to a more recent PHP version resolves compatibility issues and resolves type errors like this. You can usually update your PHP version through your hosting provider’s control panel (e.g., cPanel, Plesk) or by contacting their support team.

After updating to PHP 8.1 (or confirming you are already using it), please try resending the failed email again and let me know if the issue persists. This will help narrow down the source of the problem.

Looking forward to your update.
Thread Starter Matt Pramschufer
(@mattpramschufer)

11 months, 3 weeks ago
Hey @ibrahimsharif thanks for the quick reply. We are running PHP 8.3.21
```
### wp-server ###

server_architecture: Linux 4.14.355-275.591.amzn2.x86_64 x86_64
httpd_software: Apache
php_version: 8.3.21 64bit
php_sapi: fpm-fcgi
max_input_variables: 1000
time_limit: 120
memory_limit: 512M
admin_memory_limit: 1G
max_input_time: 60
upload_max_filesize: 1024M
php_post_max_size: 1024M
curl_version: 8.12.1 OpenSSL/3.3.3
suhosin: false
imagick_availability: true
pretty_permalinks: true
htaccess_extra_rules: true
static_robotstxt_file: false
current: 2025-06-18T13:26:47+00:00
utc-time: Wednesday, 18-Jun-25 13:26:47 UTC
server-time: 2025-06-18T09:26:47-04:00
```

Viewing 2 replies - 1 through 2 (of 2 total)

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