ilustração rejeitada por problemas técnicos, podem me dar algumas dicas de como resolver?

My first reaction was WHAT??!!!   I don't think this is aesthetically suitable for Adobe Stock, sorry.  

What is the reason for rejection given?

But just guessing here, it might be low commercial value. Over all nice colour, nice design in the background but I'm really not getting/understanding the theme of your illustration. That might be the trouble there.🤔 🤔 🙂