Have setup add to cart event and used Fb tag with a valid pixel but it doesn't fire when adding product to cart. Fb pixel tool just shows pageview events on all the pages. Have set rule for Add to cart event just to fire on product page as well
Event setup and FB tag
Based on the screenshots, everything looks like it should be working. I would suggest reviewing the selectors in the event to ensure they are correct. If you right-click and select "Inspect Element", it will pop you into the actual click element where you should be pulling the selector from. If you can verify that your selector is correct, please submit a support request to have an engineer review the configuration and the site to ensure everything is configured correctly.