My woocommerce site stopped sharing product on facebook only

Hello sir,
Your plugin was working like a charm for me till yesterday. i share all new products on facebook and twitter only through your plugin. Today i added new product it shared fine on twitter but not on facebook. Tried re authenticating facebook app but issue is still the same. when i go to products and share it again it shows success message that product is shared on facebook. but its never there. i share on page by the way. please advice.

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