Once you've already set everything up within your Zapier account but you're not receiving the leads into your 3rd party software, there might be an error during set up.
While debugging all the possibilities of the errors, this is a list that might help you find it faster:
1. If you find this error message within Zapier:
Make sure to Copy and Paste the correct Webhook (make sure no spaces are pasted). Also, just try "Resaving & Republishing" the form settings once again just to doublecheck and then try again.