My Webview won’t work perfect.
in wifi mode

it works without a problem, as soon as i switch to mobile data i see this view. cleaning the cache doesn’t really help on the smartphone either. the problem exists in iOS and Android.
If your webview is using a URL that is only accessible on your LAN it’s not accessible outside your LAN. When your phone is on mobile data, it’s outside your LAN.
myopenhab.org is not a universal reverse proxy. If the webview isn’t served up by openHAB itself, it is not available through myopenhab.org.