How to Finetune the chatGPT model to classify text to multilevel multi classification

I am preparing the model which will take the text string as input and based on context of the string, it should be classify one or more of the class from the list ( I have around 500+ classes).
I was trying to prepare the data using jsonl format and then pass the Finetune API to train the curie/davinci base model.
But it is not able to train it.

for ex:
{“prompt”: “Freelance Writing is Turning Me into a Potato”, “completion”: “comedy,playful,casual”}