Title: Critical Error when setting up Plugin
Last modified: July 25, 2021

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# Critical Error when setting up Plugin

 *  Resolved [mrboulanger1985](https://wordpress.org/support/users/mrboulanger1985/)
 * (@mrboulanger1985)
 * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-error-when-setting-up-plugin/)
 * WordPress versie 5.8
    thema: Storefront (versie 3.7.0) plugin: Mail Integration
   for Office 365/Outlook (versie 1.7.1) PHP versie 7.4.16
 * Error details
    =========== Een fout van het type E_ERROR werd veroorzaakt op 
   regelnummer 42 van het bestand /home/u3561p2038/domains/bricksaholic.com/public_html/
   wp-content/plugins/mail-integration-365/libs/vendor/guzzlehttp/guzzle/src/HandlerStack.
   php. Foutmelding: Uncaught Error: Call to undefined function GuzzleHttp\choose_handler()
   in /home/u3561p2038/domains/bricksaholic.com/public_html/wp-content/plugins/mail-
   integration-365/libs/vendor/guzzlehttp/guzzle/src/HandlerStack.php:42 Stack trace:#
   0 /home/u3561p2038/domains/bricksaholic.com/public_html/wp-content/plugins/mail-
   integration-365/libs/vendor/guzzlehttp/guzzle/src/Client.php(65): GuzzleHttp\
   HandlerStack::create() #1 /home/u3561p2038/domains/bricksaholic.com/public_html/
   wp-content/plugins/mail-integration-365/libs/vendor/league/oauth2-client/src/
   Provider/AbstractProvider.php(132): GuzzleHttp\Client->__construct(Array) #2 /
   home/u3561p2038/domains/bricksaholic.com/public_html/wp-content/plugins/mail-
   integration-365/libs/vendor/thenetworg/oauth2-azure/src/Provider/Azure.php(44):
   League\OAuth2\Client\Provider\AbstractProvider->__construct(Array, Array) #3 /
   home/u3561p2038/domains/bricksaholic.com/public_html/wp-content/plugins/mail-
   integration-365/classes/mail_integration_365/admin.php(424): TheNetworg\OAuth2\
   Clien
 * As you website is offline, I cannot see what issue could be. I have created the
   Azure AD option, and filled in the needed IDs but getting a critical error. How
   to solve?

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

 *  [edwardcross](https://wordpress.org/support/users/edwardcross/)
 * (@edwardcross)
 * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-error-when-setting-up-plugin/#post-14702747)
 * So this sound similar to this issue: [https://wordpress.org/support/topic/critical-error-216/](https://wordpress.org/support/topic/critical-error-216/)
 * Have you checked you have the Google Listings plugin? If other plugins have implemented
   these third party plugins poorly, a error will occur, that’s not much I can do
   about that as I can’t change other plugin’s code. As far as I’m aware, I have
   loaded these libraries correctly, and they are namespaced.
 * Ed
 *  Thread Starter [mrboulanger1985](https://wordpress.org/support/users/mrboulanger1985/)
 * (@mrboulanger1985)
 * [4 years, 10 months ago](https://wordpress.org/support/topic/critical-error-when-setting-up-plugin/#post-14705023)
 * It was indeed the plugin from google. Have deactivated it and now all works fine!
   
   Thanks for support!

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

The topic ‘Critical Error when setting up Plugin’ is closed to new replies.

 * ![](https://ps.w.org/mail-integration-365/assets/icon-256x256.png?rev=2817704)
 * [WPO365 | Mail Integration for Office 365 / Outlook](https://wordpress.org/plugins/mail-integration-365/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/mail-integration-365/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/mail-integration-365/)
 * [Active Topics](https://wordpress.org/support/plugin/mail-integration-365/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/mail-integration-365/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/mail-integration-365/reviews/)

 * 2 replies
 * 2 participants
 * Last reply from: [mrboulanger1985](https://wordpress.org/support/users/mrboulanger1985/)
 * Last activity: [4 years, 10 months ago](https://wordpress.org/support/topic/critical-error-when-setting-up-plugin/#post-14705023)
 * Status: resolved