Cannot Use VNC Server Kali Linux

I am recently trying to create a vnc server on my kali linux pc to allow it being controlled by my phone remotely, not only in the LAN, but also if I am at school or all around the world.

What i've made till now is NOTHING...

Every time i try to follow a tutorial on the internet the connection doesn't work, RealVNC's 'VNC Viewer' for android keeps loading and then say it had problems routing.

And tutorials on this are very rare on the web, i almost found only LAN VNCs.

I tried to open ports 5900 to 5910 and i'm using the public ip to access my pc.

I'm using, as said, VNC Viewer on my phone and ThightVNC on my kali machine..

Could you please help me?