Ettercap Doesn't Sniff Passwords

Hello everyone, I have a problem with ettercap in kali linux installed in the HDD. When I start the ARP poisoning and try to login from other computer connected to the poisoned network, ettercap doesn't show me any passwords at all; I've tried https sites and non-https, I've tried logging from windows 7 and windows 10, but nothing seem to work. Anyone know why?