Additional properties are not allowed. Unexpected property found in the input.

To fix the "Additional properties are not allowed ('meta' was unexpected) - 'messages.1'" error with a 400 status code in the OpenAI API, you need to ensure your request adheres to the API's expected format. Here are the steps to resolve this issue:

• Review the API Documentation: Ensure you are following the correct structure and parameters as specified in the OpenAI API documentation.

• Remove Unexpected Properties: Eliminate any additional properties, such as 'meta', that are not recognized by the API.

• Validate Request Payload: Double-check that the request payload only includes the fields and structure that are allowed by the API.

• Use Structured Outputs Correctly: If using Structured Outputs, ensure that your JSON schema and the corresponding request format match exactly, with no additional properties.

By aligning your request with the API's requirements, you can avoid the "Bad Request" error and successfully interact with the OpenAI API.