I am trying to invoke SageMaker through Lambda, but I am getting an error.

Here is the error:

Response
{
  "errorMessage": "An error occurred (ModelError) when calling the InvokeEndpoint operation: Received client error (400) from primary and could not load the entire response body. See https://us-east-1.console.aws.amazon.com/cloudwatch/home?region=us-east-1#logEventViewer:group=/aws/sagemaker/Endpoints/jira-endpoint in account xxxx for more information.",
  "errorType": "ModelError",
  "stackTrace": [
    "  File "/var/task/lambda_function.py", line 19, in lambda_handlern    response = runtime.invoke_endpoint(EndpointName=ENDPOINT_NAME,n",
    "  File "/var/runtime/botocore/client.py", line 565, in _api_calln    return self._make_api_call(operation_name, kwargs)n",
    "  File "/var/runtime/botocore/client.py", line 1021, in _make_api_calln    raise error_class(parsed_response, operation_name)n"
  ]
}

The model endpoint is from a prebuilt model-uri.

Here is my Lambda code:

import os, io, boto3, json, csv, base64


ENDPOINT_NAME = os.environ['ENDPOINT_NAME']
runtime= boto3.client('runtime.sagemaker')

def lambda_handler(event, context):
    project = event['project']
    # project = base64.b64decode(event['project'])
    # timeline = base64.b64decode(event['timeline'])
    
    # payload = """{}.
    #     Given the project description above, sugges a project tasklist to achieve the project goals.
    #     The project timeline is {} weeks.
    # """.format(project, timeline)

        
    payload = project
    response = runtime.invoke_endpoint(EndpointName=ENDPOINT_NAME,
                                       Body=project, ContentType="text/csv")
                                     
                                     

    result = json.loads(response["Body"].read().decode())
    print(result)
    return {
        "statusCode": 200,
        "headers": { "content-type": "application/json"},
        "body":  result
    }

Also, I am not certain in what format the SageMaker endpoint expects to receive the JSON data.

Thank you for your help!