Hi!
Test the script against http sites only, later on the course you’ll learn to bypass https. So you are getting ecvrypted content because you are using https and hsts sites.

Which http site are you using?
Also try by donwlaoding and importing the latest custom kali v1.3, this might also help to solve the issue, just install scapy and netfilterqueue on it.

Let me know how it goes!
Diego