In case not solved yet. Your iptables say:
state RELATED,ESTABLISHED
Which means that it lets pass only connections already established… that’s established by you, not by remote machines. Then you can see exceptions to this in the next rules:
state NEW tcp dpt:ssh
Which counts only for ssh, so you should add a similar rule/line for http, which you can do like this:
state NEW tcp dpt:80
Which you can do like this:
sudo iptables -I INPUT 4 -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT
(In this case I am choosing to add the new rule in the fourth line)
Remember that after editing the file you should save it like this:
sudo /etc/init.d/iptables save