I got it to work.

It was because of VPN. My VPN needed port forwarding as well.

Thanks everyone lol

Hi Everyone,

I'm trying to start a multiplayer server via Multiplayer-> New Game.

For some reason, my friends can't join me. They keep getting the error "Couldn't establish network communication with Server".

I'm on Factorio 0.13.20. I have Factorio allowed on my firewall.

I have a Netgear R7800 ...