For anyone else still having this issue here is what got it working for me:
I am running the Virtualenv setup.
I was able to see the “python3” file was there via my Windows machine.
But apparently it is a sym-link.
I ran the following command to find the actual file:
readlink -f /srv/homeassistant/bin/python3
I got the following output:
/usr/bin/python3.4
So I ran the setcap command on the actual file location:
sudo setcap ‘cap_net_bind_service=+ep’ /usr/bin/python3.4