I deleted all variations from a variable product and now it doesn’t show on PayPal Zettle anymore. What is wrong?
This is expected behaviour. A variable product without any variations is not valid for sale in WooCommerce and therefore will not sync to PayPal Zettle. In a similar way when you have a variable product and delete its last variations, the product will be removed and disappear from the PayPal Zettle library.