My friends, why my items has been rejected?

I have uploaded a file 80-80 (thumnail), 590 (preview), one file AI, 1 big file mockup. Why has been rejected? Can you please tell me where I was wrong? Thank you very much.
This is envato’s answer:
“Thank you for your submission. We have completed our review of “Logo Blockchain - Logo Company” and unfortunately we found it isn’t at the quality standard required to move forward, and you won’t be able to re-submit this item again.”

Hard to say without seeing a preview of the logo here, but the answer from Envato actually says that it does not meet the quality standards. And quality standards doesn’t mean in first place the preview or thumbnail but the logo design itself.

It’s probably not at the quality standard required to move forward.

Where to find that what quality standard should be followed?