Hook woocommerce_add_order_item_meta is replaced by woocommerce_checkout_create_order_line_item , so with your code (assuming ...
... is not working inside woocommerce_add_order_item_meta Hook. add_post_meta instead of wc_add_order_item_meta function is working ...
But I cannot work out EXACTLY when it occurs or what triggers it. So it is not easy to replicate at will. It seems to happen around cart/checkout time. (Don't say ...
This error does not relate to our theme. You will need to find out which plugin causes the error, for this purpose deactivate all third party plugins ...
woocommerce_add_order_item_meta is deprecated since version 3.0.0!
woocommerce wc_order_item_meta · woocommerce_add_order_item_meta not working.
add_action('woocommerce_add_order_item_meta'
woocommerce_add_order_item_meta not working · woocommerce_add_order_item_meta get ...
em>(If the page stops loading or shows a timeout error, then just refresh the page and the ...
woocommerce_add_order_item_meta not working.