Fix Magento 2 Add to Cart Issue and cors headers error

I am facing an ‘invalid form key’ error on my Magento 2 store when adding products to the cart. This issue is preventing customers from completing their purchases, significantly impacting sales. Also via chrome console I can see there is a CORS headre error… (Budget: €30 – €250 EUR, Jobs: CSS, HTML, JavaScript, Magento, PHP)