Ok I finally did as suggested !
Every single plugin has been disabled EXCEPT:
Woocommerce
Woocommerce product bundles (bundles used in my composite products)
Woocommerce composite products (the plugin which gives a problem with your Woocommerce module)
GP Premium
I even switched to the Twenty Seventeen Theme and Then to Storefront…
nothing – “Proceed to checkout” is still not working when your Wocommerce “module” in GP Premium is running.
I even installed a Debug plugin now and this is what I get:
PHP Fatal error: Uncaught Exception: Invalid product. in /homepages/……/wp-content/plugins/woocommerce/includes/data-stores/class-wc-product-data-store-cpt.php:149
Stack trace:
#0 /homepages/……/wp-content/plugins/woocommerce/includes/class-wc-data-store.php(149): WC_Product_Data_Store_CPT->read(Object(WC_Product))
#1 /homepages/……/wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-product.php(135): WC_Data_Store->read(Object(WC_Product))
#2 /homepages/……/wp-content/plugins/gp-premium/woocommerce/functions/functions.php(692): WC_Product->__construct(2830)
#3 /homepages/……/wp-includes/class-wp-hook.php(286): generatepress_wc_secondary_product_image(”)
#4 /homepages/……/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array)
#5 /homepages/……/wp-includes/plugin.php(453): WP_Hook->do_action(Array)
#6 /homepages/xx/xxxxxx in /homepages/xxxxxx/wp-content/plugins/woocommerce/includes/data-stores/class-wc-product-data-store-cpt.php on line 149
[28-Apr-2018 07:15:37 UTC] PHP Notice: Trying to get property of non-object in /homepages/……/wp-includes/link-template.php on line 317
……..Cheers
