Remote Access (Home-Assistant)

I’ve an issue with remote connect. Setting up the platform works well. I enter api password and authetication key via 2 FA and it seems working. But as soon as I disconnect from the Wifi I cannot connect to my hass instance. It says disconnected from Home Assistant. Connecting back to Wifi it work again. Any idea What’s going wrong?

https://cloud-space.ddns.net/r/ShKw20HF#eF3QR6ODYKfanMpmc6qLMpkIopYJYWpun7YvjdZ1vWI=