Did you avoid running sslstrip this time and any iptables rule? So it looks like you have internet connection now. So it might happen that your router has some arp spoofing protection, in that case the only thing you can do is disabling such protection or just arp spoof in one direction, as mentioned in the last lecture of Section 9 Post Connection Attacks, in that case you won’t be able to modify any response. So to confirm this is an issue with the router can you run arp -a in windows machine before and during the attack? And show the results here.
You have mentioned that it didn’t work in the virtual lab, so how did you test it if you are not able to run 2 virtual machines?