It cannot receive files from desktop, even if access to directory (Download or whatsoever) was granted. `logcat` displays a "permission denied" error. This issue only happens with Android >= 10, so I guess it's caused by the Android >= 10 storage handler. A quick fix (tested) is adding `android:requestLegacyExternalStorage="true"` to the manifest, otherwise the `MediaStore` api should be used.
This bug occurs on both of my phones (Android 10 & 11).
*** Bug 432368 has been marked as a duplicate of this bug. ***