Hey @manjii,
Yes, if you don’t have any existing pixels that you want to use associated with your Ad Account, you will need to create a new pixel.
The “Your API key is no longer valid” error may be due to using an older version of Facebook for WooCommerce – could you please confirm that you’re on the most up-to-date version of the plugin? If not, could you please update and let me know if you’re still seeing a similar error?
Finally, if you don’t want to maintain a synced catalog, you can disable the Enable product sync setting from the Facebook for WooCommerce settings once you’ve gone through the onboarding process. This will stop the regular catalog updates. If you’ve not connected the catalog to your Facebook Page shop, the products won’t be visible there. Connecting the catalog to the Page shop is a separate step, controlled outside Facebook for WooCommerce, so if you haven’t already set that up you shouldn’t see those products listed in the Facebook shop.
Looking forward to hearing from you!
Cheers!
Lindsey