Title: Fatal error: Uncaught Error: Undefined constant GuzzleHttp\ClientInterface: Last modified: January 16, 2023 --- # Fatal error: Uncaught Error: Undefined constant GuzzleHttp\ClientInterface: * Resolved [paulpbcwp](https://wordpress.org/support/users/paulpbcwp/) * (@paulpbcwp) * [3 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-undefined-constant-guzzlehttpclientinterface/) * I was trying to find a plugin to migrate my site from my localhost (xampp) to my online domain. After trying several my WP crashed and I got the following message: * `Fatal error: Uncaught Error: Undefined constant GuzzleHttp\ClientInterface:: MAJOR_VERSION in D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\ wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\vendor\guzzlehttp\guzzle\ src\Utils.php:116 Stack trace: #0 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\ wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\vendor\guzzlehttp\guzzle\ src\functions.php(71): GuzzleHttp\Utils::defaultUserAgent() #1 D:\Websites\Wordpress_Sites\ XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\plugins\wp-migration-duplicator\ admin\vendor\guzzlehttp\guzzle\src\Client.php(278): GuzzleHttp\default_user_agent()# 2 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\ plugins\wp-migration-duplicator\admin\vendor\guzzlehttp\guzzle\src\Client.php( 76): GuzzleHttp\Client->configureDefaults(Array) #3 D:\Websites\Wordpress_Sites\ XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\plugins\pymntpl-paypal- woocommerce\vendor\paymentplugins\paypal-php-sdk\src\Client\BaseHttpClient.php( 40): GuzzleHttp\Client->__construct(Array) #4 D:\Websites\Wordpress_Sites\XAMPP\ htdocs\paulbohannaceramics\wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\ src\WPPayPalClient.php(45): PaymentPlugins\PayPalSDK\Client\BaseHttpClient->__construct( Array) #5 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\ wp-content\plugins\pymntpl-paypal-woocommerce\src\Main.php(143): PaymentPlugins\ WooCommerce\PPCP\WPPayPalClient->__construct(Object(PaymentPlugins\WooCommerce\ PPCP\Admin\Settings\APISettings), Object(PaymentPlugins\WooCommerce\PPCP\Logger))# 6 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\ plugins\pymntpl-paypal-woocommerce\src\Container\AbstractResolver.php(18): PaymentPlugins\ WooCommerce\PPCP\Main->PaymentPlugins\WooCommerce\PPCP\{closure}(Object(PaymentPlugins\ WooCommerce\PPCP\Container\Container)) #7 D:\Websites\Wordpress_Sites\XAMPP\htdocs\ paulbohannaceramics\wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\src\ Container\BaseResolver.php(13): PaymentPlugins\WooCommerce\PPCP\Container\AbstractResolver- >resolve(Object(PaymentPlugins\WooCommerce\PPCP\Container\Container)) #8 D:\Websites\ Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\plugins\ pymntpl-paypal-woocommerce\src\Container\Container.php(25): PaymentPlugins\WooCommerce\ PPCP\Container\BaseResolver->get(Object(PaymentPlugins\WooCommerce\PPCP\Container\ Container)) #9 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\ wp-content\plugins\pymntpl-paypal-woocommerce\src\Rest\RestController.php(47): PaymentPlugins\WooCommerce\PPCP\Container\Container->get('PaymentPlugins\\...')# 10 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp- content\plugins\pymntpl-paypal-woocommerce\src\Rest\RestController.php(42): PaymentPlugins\ WooCommerce\PPCP\Rest\RestController->initialize() #11 D:\Websites\Wordpress_Sites\ XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\plugins\pymntpl-paypal- woocommerce\src\Main.php(179): PaymentPlugins\WooCommerce\PPCP\Rest\RestController- >__construct(Object(PaymentPlugins\WooCommerce\PPCP\Container\Container)) #12 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\ plugins\pymntpl-paypal-woocommerce\src\Container\AbstractResolver.php(18): PaymentPlugins\ WooCommerce\PPCP\Main->PaymentPlugins\WooCommerce\PPCP\{closure}(Object(PaymentPlugins\ WooCommerce\PPCP\Container\Container)) #13 D:\Websites\Wordpress_Sites\XAMPP\ htdocs\paulbohannaceramics\wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\ src\Container\BaseResolver.php(13): PaymentPlugins\WooCommerce\PPCP\Container\ AbstractResolver->resolve(Object(PaymentPlugins\WooCommerce\PPCP\Container\Container))# 14 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp- content\plugins\pymntpl-paypal-woocommerce\src\Container\Container.php(25): PaymentPlugins\ WooCommerce\PPCP\Container\BaseResolver->get(Object(PaymentPlugins\WooCommerce\ PPCP\Container\Container)) #15 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\ wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\packages\blocks\src\Package. php(43): PaymentPlugins\WooCommerce\PPCP\Container\Container->get('PaymentPlugins\\...')# 16 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp- content\plugins\pymntpl-paypal-woocommerce\src\Container\AbstractResolver.php( 18): PaymentPlugins\PPCP\Blocks\Package->PaymentPlugins\PPCP\Blocks\{closure}( Object(PaymentPlugins\WooCommerce\PPCP\Container\Container)) #17 D:\Websites\ Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\plugins\ pymntpl-paypal-woocommerce\src\Container\BaseResolver.php(13): PaymentPlugins\ WooCommerce\PPCP\Container\AbstractResolver->resolve(Object(PaymentPlugins\WooCommerce\ PPCP\Container\Container)) #18 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\ wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\src\Container\Container. php(25): PaymentPlugins\WooCommerce\PPCP\Container\BaseResolver->get(Object(PaymentPlugins\ WooCommerce\PPCP\Container\Container)) #19 D:\Websites\Wordpress_Sites\XAMPP\ htdocs\paulbohannaceramics\wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\ packages\blocks\src\Package.php(75): PaymentPlugins\WooCommerce\PPCP\Container\ Container->get('PaymentPlugins\\...') #20 D:\Websites\Wordpress_Sites\XAMPP\htdocs\ paulbohannaceramics\wordpress\wp-content\plugins\pymntpl-paypal-woocommerce\src\ Package\PackageController.php(50): PaymentPlugins\PPCP\Blocks\Package->initialize()# 21 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp- includes\class-wp-hook.php(308): PaymentPlugins\WooCommerce\PPCP\Package\PackageController- >initialize_packages('') #22 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\ wordpress\wp-includes\class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)# 23 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp- includes\plugin.php(517): WP_Hook->do_action(Array) #24 D:\Websites\Wordpress_Sites\ XAMPP\htdocs\paulbohannaceramics\wordpress\wp-content\plugins\woocommerce\includes\ class-woocommerce.php(667): do_action('woocommerce_ini...') #25 D:\Websites\Wordpress_Sites\ XAMPP\htdocs\paulbohannaceramics\wordpress\wp-includes\class-wp-hook.php(308): WooCommerce->init('') #26 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\ wordpress\wp-includes\class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)# 27 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp- includes\plugin.php(517): WP_Hook->do_action(Array) #28 D:\Websites\Wordpress_Sites\ XAMPP\htdocs\paulbohannaceramics\wordpress\wp-settings.php(617): do_action('init')# 29 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp- config.php(96): require_once('D:\\Websites\\Wor...') #30 D:\Websites\Wordpress_Sites\ XAMPP\htdocs\paulbohannaceramics\wordpress\wp-load.php(50): require_once('D:\\ Websites\\Wor...') #31 D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\ wordpress\wp-admin\admin.php(34): require_once('D:\\Websites\\Wor...') #32 D:\ Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp-admin\ plugin-install.php(16): require_once('D:\\Websites\\Wor...') #33 {main} thrown in D:\Websites\Wordpress_Sites\XAMPP\htdocs\paulbohannaceramics\wordpress\wp- content\plugins\pymntpl-paypal-woocommerce\vendor\guzzlehttp\guzzle\src\Utils. php on line 116` * I am now unable to access anything except the message above. I have no idea what to do. Please help. Thank you. Viewing 1 replies (of 1 total) * Thread Starter [paulpbcwp](https://wordpress.org/support/users/paulpbcwp/) * (@paulpbcwp) * [3 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-undefined-constant-guzzlehttpclientinterface/#post-16377820) * I think I’ve solved it myself (deleted plugin directories until it worked). Viewing 1 replies (of 1 total) The topic ‘Fatal error: Uncaught Error: Undefined constant GuzzleHttp\ClientInterface:’ is closed to new replies. ## Tags * [Site Crashed](https://wordpress.org/support/topic-tag/site-crashed/) * In: [Localhost Installs](https://wordpress.org/support/forum/localhost-installs/) * 1 reply * 1 participant * Last reply from: [paulpbcwp](https://wordpress.org/support/users/paulpbcwp/) * Last activity: [3 years, 4 months ago](https://wordpress.org/support/topic/fatal-error-uncaught-error-undefined-constant-guzzlehttpclientinterface/#post-16377820) * Status: resolved ## Topics ### Topics with no replies ### Non-support topics ### Resolved topics ### Unresolved topics ### All topics