I am learning AWS and trying to migrate my RDS Postgres to AWS Neptune. For that, I created a Database Migration Task in AWS DMS. It seems to pull the data and store it in s3 in csv format and use the csv format to dump data in aws neptune.

The first part where it store RDS data to s3 is working fine, i can see edge and vertex folders in my s3 bucket with csv files in them but the second half fails with the following error:

2024-06-15T09:23:42:100351 [TASK_MANAGER    ]D:  BuildAWSError: responseCode 500 message 
{
    "detailedMessage": "Unable to connect to s3 endpoint. Provided source = s3://<s3-bucket-path>/vertex/locations/locations-vertex-2-00000001.csv_1718443360570395 and region = us-east-1. Please verify your S3 configuration.",
    "code": "InternalFailureException",
    "requestId": "9ac80d9a-6336-6940-b9d7-7493fcffdf1c",
    "message": "Unable to connect to s3 endpoint. Provided source = s3://<s3-bucket-path>/vertex/locations/locations-vertex-2-00000001.csv_1718443360570395 and region = us-east-1. Please verify your S3 configuration."
}

It seems like i somehow need to provide a role that has access to s3 which I already did for target endpoint and neptune itself, granted AmazonS3FullAccess policy to the role after which the first half started to work.

Also, i’ve turned off ‘Block Public Access’ from bucket and this is the bucket policy:

{
    "Version": "2012-10-17",
    "Id": "<id>",
    "Statement": [
        {
            "Sid": "Stmt1718035983652",
            "Effect": "Allow",
            "Principal": "*",
            "Action": "s3:*",
            "Resource": "arn:aws:s3:::<bucket-name>/*"
        }
    ]
}

Can someone please guide me in what I might be missing?