If you are using Fedora server as a mail server you would not need ports 80 and 443 open. From what I remember only port 22 is open by default. I think firewalld comes preinstalled on Fedora, not 100% sure. Did you disable firewalld and install iptabled-services ?
You can use the netstat command to see what ports are on, then allow those ports in iptables or firewalld
To open the ports with iptables
iptables -A INPUT -p tcp -m conntrack --ctstate NEW --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -m conntrack --ctstate NEW --dport 443 -j ACCEPT
iptables -A OUTPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
The first one will accept new connections to port 80
The second one will accept new connections to port 443
the third command will allow established connections to go out.