Problem with submission to the leader board

I’m trying to upload the test results to the leaderboard but got refused by the system (red cross), any idea? Thanks in advance for your help!
My account name is: Nedelcho

Hi @ageorgiev97,

I took a look at your submissions - it looks like you’re using the wrong dataset. Can you please re-download the public test set and submit again.

Thanks,
Tullie