Newbe - App requires Local Wifi?

I am a new user of Home Assistant. I have setup my HomeAssistant on my QNAP Nas in a Docker. I want my app be able to control my home also when away from home. I have made a trial nabu-casa account, and was expecting my Home Asistant app to automatically to use the cloud connection when away from home. But there is no connection unless I’m on a local network with my phone. I think I have everything configured correctly, since I am able to use the Remote access url to control everything via a browser on my phone (also when not on wifi). But it does not work from the app on my mobile phone. I have tried both the Android and the Iphone version. It works via a browser on the phone, but not via the app. Is this as expected ?

Cheers,
Jesper