Getting error {"detail":"openai error: Please submit an `input`."}

I have integrated gptcache in a server application.
on calling below method ,
openai_response = openai.ChatCompletion.create(

with data,
payload = {

    'model': 'gpt-3.5-turbo',
    'messages': [{"role": "system", "content": "You are a helpful assistant."},
                 {'role': 'user', 'content': user_question}]

am getting error:
{“detail”:“openai error: Please submit an input.”}

The issue is seen when embedding model used for cache config is “openai”, when used model “ONNX”, able to get response from open ai.