That is correct so we don't know what mistake you had to cause your sentence to be rejected.
Next time be sure to FOLLOW THESE INSTRUCTIONS.
TIPS TO MAKE LEARNING EASIER + HOW TO REPORT A PROBLEM
And check out the Greek Forum here with more links.
<h1>Please do not post comments about rejected sentences if you have not first made a REPORT</h1>
And check out the Greek Forum here with more links. https://forum.duolingo.com/topic/936