More than 1 router. The most common problem I come across is people who are behind 2 or more …

How to open ports in Windows Firewall | Windows Central Sep 22, 2017 How to Open Ports and Set Up Port Forwarding on Your Feb 20, 2018

May 08, 2015

Aug 19, 2016 Airport Won't allow port forwarding a… - Apple Community

Port 25565 Just Won't Open(SOLVED) - Server Support and

How To Open Firewall Ports In Windows 10 | Tom's Hardware Open firewall ports in Windows 10 You can manually permit a program to access the internet by opening a firewall port. You will need to know what port it uses and the protocol to make this work.