I’m a beginner and I keep getting this error message when testing a Lambda function. I’m trying to do a simple write file to an S3 directory bucket.

Here is the PHP code:

import json
import boto3
import os

def lambda_handler(event, context):
    s3 = boto3.client('s3')
    bucket_name = 'pollytts--use1-az6--x-s3'
    object_key = 'test-file.txt'
    file_content = 'Hello, this is a test file.'

    try:
        response = s3.put_object(
            Bucket=bucket_name,
            Key=object_key,
            Body=file_content
        )
        return {
            'statusCode': 200,
            'body': json.dumps('File uploaded successfully!')
        }
    except Exception as e:
        return {
            'statusCode': 500,
            'body': json.dumps(f'Error uploading file to S3: {str(e)}')
        }

Here is the error:

Response
{
  "statusCode": 500,
  "body": ""Error uploading file to S3: An error occurred (AccessDenied) when calling the CreateSession operation: Access Denied""
}

Function Logs
START RequestId: 29a9828b-32ce-40ef-a247-2b7fcdfd5f45 Version: $LATEST
END RequestId: 29a9828b-32ce-40ef-a247-2b7fcdfd5f45
REPORT RequestId: 29a9828b-32ce-40ef-a247-2b7fcdfd5f45  Duration: 610.16 ms Billed Duration: 611 ms Memory Size: 128 MB Max Memory Used: 83 MB

Request ID
29a9828b-32ce-40ef-a247-2b7fcdfd5f45

I added a user and added permission policy with all access to S3 actions, and the execution role of the lambda function also has the permissions.