Running into a bizarre issue I have an android Ebook reader when WIFI is not available I will sometimes connect it to my cell phone using a tethering app that works over usb debugging, I can confirm the tablet has a working internet connection Play services work and I can access internet resources through browsers and other apps. However F-Droid will show a constant no internet error and fail to resolve host names when updating I have a suspicion that something is overriding the VPN the tethering app creates and preventing F-Droid from using this connection. Does anyone have any idea what causes this and how to force F-Droid to use network connections other than WIFI and Cell data?
Why do you need a special tethering App? Which one? Any phone will offer you WiFi hotspot and USB tethering out of the box?
Think this is a known issue unfortunately.
These reverse connections are odd. 
Would be nice to see a log of this.
USB tethering via VPN is often not detected as an internet connection by some app.
A workaround I founded for F-Droid is to the “Latests” tab and scroll from the top to trigger a repo update. In this case the internet connection will not be checked and you can update your app.
See network access via gnirehtet does not work (#2111) · Issues · F-Droid / Client · GitLab