Problems to connect with iOS App when in an external WLAN

I used a subdomain inside my home network “” to connect to my openhab server and from outside the myopenhab service. This works fine when I am at home or outside with using a mobile provider internet connection (like LTE). But when I am in another WLAN outside (Hotel, friends, etc), the app did not use the myopenhab service and tries to connect over the (w)lan settings - and this fails. I think it is a bug.
I would expect that the app try first if the local server connection is reachable, when not, it should try the myopenhab service.

Yes the app will try local first then remote.

In my case it only works if i am at home, then the app uses local, or when I am in a cellular network, then the app uses the myopenhab account. When I am in another WLAN network (from friends, family, or something else), the app cannot connect to my myopenhab account. So it seems that in a external WLAN the app did not “understand” that I am not at home and did not try myopenhab for connection.