First Template...Hard rejected?? Help me improve

Looking for some feedback to help me improve as a developer/designer. My first template submission to themeforest was hard rejected saying “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.”

It was a React GatsbyJS single page landing page. Demo here:
https://demos.simplecode.io/gatsby-starters/bluecircle/

What do some of you think could be the reasons?