Title: SMTP connection problem
Last modified: September 3, 2025

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# SMTP connection problem

 *  [brendanapimani](https://wordpress.org/support/users/brendanapimani/)
 * (@brendanapimani)
 * [7 months, 1 week ago](https://wordpress.org/support/topic/smtp-connection-problem-2/)
 * Hello, I am unable to connect to SMTP despite entering the correct information.
   I am using version 2.2.1 of the Solid Mail plugin.
 * I am getting these errors. How can I resolve the issue?
 *     ```wp-block-code
       wordpress-1  | NOTICE: PHP message: PHP Fatal error:  Uncaught Error: Class "WP_PHPMailer" not found in /var/www/wp-content/plugins/wp-smtp/src/Mail/SolidMailer.php:24wordpress-1  | Stack trace:wordpress-1  | #0 /var/www/wp-content/plugins/multilingualpress/vendor/composer/ClassLoader.php(576): include()wordpress-1  | #1 /var/www/wp-content/plugins/multilingualpress/vendor/composer/ClassLoader.php(427): Composer\Autoload\{closure}('/var/www/wp-con...')wordpress-1  | #2 /var/www/wp-content/plugins/wp-smtp/src/Mail/Admin/ScreenConnectors.php(142): Composer\Autoload\ClassLoader->loadClass('SolidWP\\Mail\\So...')wordpress-1  | #3 /var/www/wp-includes/class-wp-hook.php(324): SolidWP\Mail\Admin\ScreenConnectors->send_test_email('')wordpress-1  | #4 /var/www/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters('', Array)wordpress-1  | #5 /var/www/wp-includes/plugin.php(517): WP_Hook->do_action(Array)wordpress-1  | #6 /var/www/wp-admin/admin-ajax.php(192): do_action('wp_ajax_solidwp...')wordpress-1  | #7 {main}wordpress-1  |   thrown in /var/www/wp-content/plugins/wp-smtp/src/Mail/SolidMailer.php on line 24
       ```
   
 * Thank you for your feedback and assistance!

Viewing 3 replies - 1 through 3 (of 3 total)

 *  [Ben Meredith](https://wordpress.org/support/users/benmeredithgmailcom/)
 * (@benmeredithgmailcom)
 * [7 months, 1 week ago](https://wordpress.org/support/topic/smtp-connection-problem-2/#post-18626571)
 * Hey [@brendanapimani](https://wordpress.org/support/users/brendanapimani/) ! 
   
   Glad you reached out here. The error `Class "WP_PHPMailer" not found` indicates
   a problem “above the level” of Solid Mail. I’ll explain in detail below, but 
   the “quick fix” here is to ensure that your WordPress installation itself is 
   complete and that nothing has prevented the default WP_PHPMailer class from loading.
   That class can sometimes be blocked by overzealous hosts or maybe a firewall 
   plugin or something, or it could be evidence of your WordPress installation being
   somehow incomplete. The short answer: this indicates a non-standard WordPress
   installation, and Solid Mail requires that class to do anything. Longer explanation:
 * WordPress creates a PHP “class” to send emails, which is essentially extending
   the PHPMailer class. That class creates a `wp_mail()` function, which in turn
   is what Solid Mail (and other plugins) can extend to make email more reliable
   in WordPress. You can read more about that whole process here: [https://solidwp.com/documentation/general-wp/learn-more/understanding-email-deliverability-in-wordpress/](https://solidwp.com/documentation/general-wp/learn-more/understanding-email-deliverability-in-wordpress/)
 * All of that is built on the premise that WP_PHPMailer is available. On your site,
   it’s saying that calss is not available, which is something either your web host
   has control over, or some third-party software is hijacking WP_PHPMailer in a
   way that makes Solid Mail not able to function on your site.
 *  Thread Starter [brendanapimani](https://wordpress.org/support/users/brendanapimani/)
 * (@brendanapimani)
 * [7 months, 1 week ago](https://wordpress.org/support/topic/smtp-connection-problem-2/#post-18627362)
 * Hello [@benmeredithgmailcom](https://wordpress.org/support/users/benmeredithgmailcom/),
 * Thank you for your feedback and detailed explanations!
 * What I don’t understand is that just a few days ago, my emails were working perfectly
   and sending fine. How can the ‘WP_PHPMailer’ class disappear?
 * In addition, I had the Check & Log Email plugin installed, but I uninstalled 
   it in case it was causing incompatibility with Solid Mail. I also updated Solid
   Mail recently.
 * I am on a multisite, and this only affects my main site, apimani.fr, even though
   I have the same configuration on pro.apimani.fr. The only difference, in my opinion,
   is the SMTP connection, which is different (because the email and password are
   different, but otherwise it is the same mail server).
 * Do you have any ideas for tests I could run, ways to restore the ‘WP_PHPMailer’
   class, or anything else that might help me?
 * Thank you for your help and your time.
 *  Thread Starter [brendanapimani](https://wordpress.org/support/users/brendanapimani/)
 * (@brendanapimani)
 * [7 months ago](https://wordpress.org/support/topic/smtp-connection-problem-2/#post-18634055)
 * Hello [@benmeredithgmailcom](https://wordpress.org/support/users/benmeredithgmailcom/),
 * Any news ?
 * Thank you for your help and your time.

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘SMTP connection problem’ is closed to new replies.

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 * 3 replies
 * 2 participants
 * Last reply from: [brendanapimani](https://wordpress.org/support/users/brendanapimani/)
 * Last activity: [7 months ago](https://wordpress.org/support/topic/smtp-connection-problem-2/#post-18634055)
 * Status: not resolved