Live view over internet not working – NUUO iViewer Review

Livevirw stopped working. I can access everything from remote locations, since dns is set up properly (devices, cameras, system, no problem). Liveview only works via LAN. It works like this: I install the app, set up new server with proper DNS, ports, etc. It works ONCE and then nothing. I can repeat this like 10 times and the behaviour persist. My upload ranges from 15-40mbps via LTE, but it does not work
Review by Nuuo NVRmini2 Ne-4080 on NUUO iViewer.