App Lounge: no conncetion via USB-C cable

Using App Loung version 2.10.1

The App Lounge lists apps and updates normally if my device (Xiaomi MI A1) is using a WLAN connection. So there seems not to b a general issue with App Lounge.
When using an USB-C ethernet connection instead of WLAN, App Lounge says “no connection” in ALL of the screen, i.d. even the “Settings” screen ceases to work.
I set the App Lounge option “Use unmetered connection only” (german: “Nur in unlimitierten Netzwerken”) to false, with no effect.

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