Title: Uncaught Error: Call to undefined function GuzzleHttp\choose_handler()
Last modified: August 20, 2021

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# Uncaught Error: Call to undefined function GuzzleHttp\choose_handler()

 *  [conor31](https://wordpress.org/support/users/conor31/)
 * (@conor31)
 * [4 years, 9 months ago](https://wordpress.org/support/topic/uncaught-error-call-to-undefined-function-guzzlehttpchoose_handler-2/)
 * Mailjet plugin has stopped functioning properly and getting this on every login
   attempt as well as anytime i open mailjet plugin. Also tried to install elemontor
   update and crashed whole site.
 *     ```
       Fatal error: Uncaught Error: Call to undefined function GuzzleHttp\choose_handler()
       in /home/customer/www/mypethq.io/public_html/wp-content/plugins/mailjet-for-wordpress/vendor/guzzlehttp/guzzle/src/HandlerStack.php on line 40
   
       Call stack:
   
       GuzzleHttp\HandlerStack::create()
       wp-content/plugins/mailjet-for-wordpress/vendor/guzzlehttp/guzzle/src/Client.php:65
       GuzzleHttp\Client::__construct()
       wp-content/plugins/mailjet-for-wordpress/vendor/mailjet/mailjet-apiv3-php/src/Mailjet/Request.php:43
       Mailjet\Request::__construct()
       wp-content/plugins/mailjet-for-wordpress/vendor/mailjet/mailjet-apiv3-php/src/Mailjet/Client.php:125
       Mailjet\Client::_call()
       wp-content/plugins/mailjet-for-wordpress/vendor/mailjet/mailjet-apiv3-php/src/Mailjet/Client.php:188
       Mailjet\Client::get()
       wp-content/plugins/mailjet-for-wordpress/src/includes/MailjetApi.php:364
       MailjetPlugin\I\MailjetApi::isValidAPICredentials()
       wp-content/plugins/mailjet-for-wordpress/src/includes/MailjetSettings.php:196
       MailjetPlugin\I\MailjetSettings::addMailjetActions()
       wp-content/plugins/mailjet-for-wordpress/src/includes/MailjetSettings.php:90
       MailjetPlugin\I\MailjetSettings::mailjet_settings_init()
       wp-includes/class-wp-hook.php:303
       WP_Hook::apply_filters()
       wp-includes/class-wp-hook.php:327
       WP_Hook::do_action()
       wp-includes/plugin.php:470
       do_action()
       wp-settings.php:578
       require_once()
       wp-config.php:77
       require_once()
       wp-load.php:50
       require_once()
       wp-admin/admin.php:34
       ```
   

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

 *  Moderator [t-p](https://wordpress.org/support/users/t-p/)
 * (@t-p)
 * [4 years, 9 months ago](https://wordpress.org/support/topic/uncaught-error-call-to-undefined-function-guzzlehttpchoose_handler-2/#post-14789903)
 * Your `mailjet-for-wordpress` plugin seems to be the error.
 * Access your server via [SFTP or FTP](https://wordpress.org/support/article/ftp-clients/),
   or a file manager in your hosting account’s control panel (consult your hosting
   provider’s documentation for specifics on these), navigate to /wp-content/
    plugins/
   and rename or delete the directory of `mailjet-for-wordpress` plugin.
 * Next, report the issue to that plugin’s developers.
 *  [mehmetnadir](https://wordpress.org/support/users/mehmetnadir/)
 * (@mehmetnadir)
 * [4 years, 5 months ago](https://wordpress.org/support/topic/uncaught-error-call-to-undefined-function-guzzlehttpchoose_handler-2/#post-15199319)
 * There is a problem with the latest version of this plugin. I solved the problem
   by installing the old version. The version number I installed is 5.2.8.
    You 
   can download it by selecting the version number from the bottom of this page.
   After disabling and deleting the mailjet plugin from the plugins page on your
   site, and installing the 5.2.8 you downloaded, the problem will be solved. Your
   data will not be deleted when you delete the add-on, so don’t worry.
 * URL: [https://wordpress.org/plugins/mailjet-for-wordpress/advanced/](https://wordpress.org/plugins/mailjet-for-wordpress/advanced/)

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

The topic ‘Uncaught Error: Call to undefined function GuzzleHttp\choose_handler()’
is closed to new replies.

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 2 replies
 * 3 participants
 * Last reply from: [mehmetnadir](https://wordpress.org/support/users/mehmetnadir/)
 * Last activity: [4 years, 5 months ago](https://wordpress.org/support/topic/uncaught-error-call-to-undefined-function-guzzlehttpchoose_handler-2/#post-15199319)
 * Status: not resolved

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