I want to use my Android device as Proxy Server. I was trying to use Proxy Server app and Server Ultimate app. When I connect through WIFI - a proxy server is working, but when I disconnect from wifi and I trying to connect through my public IP, it doesn't work. Maybe I need to edit some firewall rules on my device?
I use an HTC one m8.
A problem with a mobile provider. Most mobile providers block incoming connection to the phone. But you can connect with your provider and ask to allow the incoming connection, but it's not a good idea and sometimes it's not possible.