I got this wrong because I initially wrote "How were you feeling yesterday." Then I realized that was wrong and changed "you" to "she" -- but forgot to change "were" to "was." So I know why my answer was wrong.
HOWEVER... The correct answer DL offered was... You used the wrong word. How were they feeling yesterday?... and "they" was underlined.
I reported this as the Correct Solution is unnatural or has an error, but I mention it here as well, in someone needs to know the background.
The system sometimes reports a wrong word as being wrong. Not sure why. It likely does not expect it at the position in sentence and evaluates it as an error, even though another word is wrong or word order is wrong. So do not always believe the underlined word, check (or czech) the entire sentence. There is not much technically we can do to fix it.