WooCommerce PayPal Payments breaks coupon page

After the update of WooCommerce PayPal Payments to the version 2.3.1, I’m not able anymore to create a new coupon code.
When I try to add a new coupon code I receive this error:

Warning: Creating default object from empty value in /home/customer/www/forbicielioathome.com/public_html/wp-admin/includes/post.php on line 787

Fatal error: Uncaught TypeError: Argument 1 passed to WooCommerce\PayPalCommerce\WcGateway\Gateway\OXXO\OXXO::WooCommerce\PayPalCommerce\WcGateway\Gateway\OXXO\{closure}() must be of the type string, null given, called in /home/customer/www/forbicielioathome.com/public_html/wp-includes/class-wp-hook.php on line 312 and defined in /home/customer/www/forbicielioathome.com/public_html/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-wc-gateway/src/Gateway/OXXO/OXXO.php:157 Stack trace: #0 /home/customer/www/forbicielioathome.com/public_html/wp-includes/class-wp-hook.php(312): WooCommerce\PayPalCommerce\WcGateway\Gateway\OXXO\OXXO->WooCommerce\PayPalCommerce\WcGateway\Gateway\OXXO\{closure}(NULL) #1 /home/customer/www/forbicielioathome.com/public_html/wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters(NULL, Array) #2 /home/customer/www/forbicielioathome.com/public_html/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #3 /home/customer/www/forbicielioathome.com/public_html/wp-admin/includes/meta-boxes. in /home/customer/www/forbicielioathome.com/public_html/wp-content/plugins/woocommerce-paypal-payments/modules/ppcp-wc-gateway/src/Gateway/OXXO/OXXO.php on line 157

Could you please help me?
Thank you

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