Title: Error when activating plugin
Last modified: September 15, 2020

---

# Error when activating plugin

 *  Resolved [jtomppo](https://wordpress.org/support/users/jtomppo/)
 * (@jtomppo)
 * [5 years, 6 months ago](https://wordpress.org/support/topic/error-when-activating-plugin-40/)
 * I got the following critical error message after downloading and activating this
   plugin. It basically bricked my webshop and I had to manually delete the plugin
   in order to use my webshop again.
 * The first sentence says there is an error typed E_ERROR on line 36 in file …/
   wp-content/plugins/woo-izettle-integration/includes/izettle-integration-iz-products.
   php
 * Tiedoston /home/ultrafinn/public_html/wp-content/plugins/woo-izettle-integration/
   includes/izettle-integration-iz-products.php rivillä 36 havaittiin virhe lajia
   E_ERROR.
 * Error message: Uncaught Error: Undefined class constant ‘RESOURCETYPE_THREAD’
   in /home/ultrafinn/public_html/wp-content/plugins/woo-izettle-integration/includes/
   izettle-integration-iz-products.php:36
    Stack trace: #0 /home/ultrafinn/public_html/
   wp-content/plugins/woo-izettle-integration/includes/izettle-integration-iz-products.
   php(836): Woo_iZettle_Integration_Products_From_iZettle_Handler->__construct()#
   1 /home/ultrafinn/public_html/wp-content/plugins/woo-izettle-integration/woo-
   izettle-integration.php(160): require_once(‘/home/ultrafinn…’) #2 /home/ultrafinn/
   public_html/wp-includes/class-wp-hook.php(287): WC_iZettle_Integration->init(”)#
   3 /home/ultrafinn/public_html/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(
   NULL, Array) #4 /home/ultrafinn/public_html/wp-includes/plugin.php(478): WP_Hook-
   >do_action(Array) #5 /home/ultrafinn/public_html/wp-settings.php(546): do_action(‘
   init’) #6 /home/ultrafinn/public_html/wp-config.php(86): require_once(‘/home/
   ultrafinn…’) #7 /home/ultrafinn/public_html/wp-load.php(3

Viewing 1 replies (of 1 total)

 *  Plugin Author [bjorntech](https://wordpress.org/support/users/bjorntech/)
 * (@bjorntech)
 * [5 years, 6 months ago](https://wordpress.org/support/topic/error-when-activating-plugin-40/#post-13407330)
 * Hi,
 * Thanks for reporting and sorry to hear that you experienced problems.
 * This problem seems to be appearing in rare cases and I have a fix for it that
   I can send to you.
 * Send me an email at [hello@bjorntech.com](https://wordpress.org/support/topic/error-when-activating-plugin-40/hello@bjorntech.com?output_format=md)
   for a link to a fixed version. This version is in release candidate status and
   will be released soon so it is stable.
 * /tobbe

Viewing 1 replies (of 1 total)

The topic ‘Error when activating plugin’ is closed to new replies.

 * ![](https://ps.w.org/woo-izettle-integration/assets/icon.svg?rev=3345176)
 * [BjornTech PayPal POS integration for WooCommerce](https://wordpress.org/plugins/woo-izettle-integration/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/woo-izettle-integration/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/woo-izettle-integration/)
 * [Active Topics](https://wordpress.org/support/plugin/woo-izettle-integration/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/woo-izettle-integration/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/woo-izettle-integration/reviews/)

## Tags

 * [critical error](https://wordpress.org/support/topic-tag/critical-error/)
 * [E_ERROR](https://wordpress.org/support/topic-tag/e_error/)

 * 1 reply
 * 2 participants
 * Last reply from: [bjorntech](https://wordpress.org/support/users/bjorntech/)
 * Last activity: [5 years, 6 months ago](https://wordpress.org/support/topic/error-when-activating-plugin-40/#post-13407330)
 * Status: resolved