The iZettle plugin gives one of the following errors

CRITICAL Uncaught TypeError: Argument 1 passed to Wetail\Wiz\Inventory::get_variant_inventory() must be of the type string, null given, called in /wp-content/plugins/woocommerce-izettle/includes/Woo/class-woo-inventory.php

To correct this you have to reset the WooCommerce iZettle settings and login again.

Follow these steps:

• Navigate to WooCommerce->iZettle and check Debug Mode

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Click Reset Settings and Login into iZettle again