Hi
@Rachbob
The problem is with the network you want to connect to.
When you connect to your
WIFI network, access is local via
LAN (Local Area Network) and logically you can access your computer with an IP address (192.168.x.x)
But when you connect to a
3G or 4G network you do so to a
WAN (Wide Area Network) and since your computer is not on that network it cannot be accessed. If you need to put your computer on that network, you should talk to your Internet ISP so that it gives you a Public IP that can be accessed from anywhere in the world
If you want to know what your public IP is, click on the following link:
https://es.geoipview.com/
With this explanation it should already be clear to you.