After I update my old and discontinued Remote Desktop Android APP to the most recently version, no more connecting from 4G.
If I try connect from Wi-Fi, this work well.
If I try connect from other PC in other network, the native Remote desktop from Windows and the RDP APP from Microsoft Store, both work well, including running this APP from Lumia 950 using Internet share from the same Android that isn't working.
If I try use this URL No-IP or IP direct as gateway, the APP find a connection but fail because this isn't a gateway.
Note: My network external port opened for this service isn't a default RDP.