Different embassies may have different reasons for rejection. But just to let you know that my application from Mumbai, India was rejected because of a lack of current source of income. I had applied under the soft power category and had more than sufficient balance in my bank account. In my understanding , soft power application does not require you to have a current employment or business. However they did not consider my soft power activity as a valid reason and simply rejected it. I'm just sharing my story about the Mumbai consulate. If you're applying from another region, you may consider researching or reading comments about the specific embassy you're applying to. Hope it helps..