Fatal error: Call to a member function is_type() on boolean in..

Sorry. Didnt see your post. Fixed it.
Thank you.
For others who didnt see:

/wp-content/plugins/woocommerce-product-stock-alert/classes

File: class-woo-product-stock-alert-admin.php

Change line 231 to

if( is_object($product_obj) && $product_obj->is_type(‘variable’) ) {

Thanks for your feedback.

I’m actually trying to make it multilingual with the Polylang plugin.

Any idea?

Here is my thread: https://www.ads-software.com/support/topic/multilingual-integration-with-polylang-wc-product-stock-alert-plugin