The input provided is not in the expected format. Ensure that the input data is structured as an array of messages to proceed correctly.

The 400 status error in the OpenAI API, in this case, is likely due to the invalid format or content of the request. Here are the key reasons:

1. Invalid Request Format: The error message indicates that the input is not of the expected type ('array' - 'messages'). This suggests that the structure of your request does not match what the API expects[4%.

2. Incorrect Data Payload: The API is expecting a specific format for the input data, and your request does not comply with this format. This could be due to incorrect formatting, missing fields, or extra fields that are not recognized by the API.

3. Hidden Characters or Typographical Errors: There might be hidden characters or typographical errors in the API key or other parts of the request, which can lead to a "Bad Request" error.

4. API Key Issues: Although not directly mentioned in the error, incorrect or expired API keys can also lead to 400 errors, though this seems less likely given the specific error message about the 'messages' type.