I wanted to import this article into Lingq: Нам скоро разрешат говорить «звОнит». From my iPad I “shared” the URL with the Lingq app. The default “course” was “Quick Imports.” I tried twice. Failed both times. For some reason, I tried selecting a different course. Success. Finally, I again tried importing into “Quick Imports,” and it succeeded.
As usual, some helpful message besides “failed” would be ever so useful. The bottom line: strange behavior + no diagnostic information.