I created create_s3.tf file but it is not working

Terraform
#1

What is wrong with my code ?

resource "aws_s3_bucket" "demo" {
        bucket = "demo-2441139"
        tags   = {
                Description = "Demo for Terraform S3"
        }
}


resource "aws_s3_object" "demo-2024" {
        content = "/home/rajarshi/terraform/aws/s3_test.txt"
        key     = "s3_test.txt"
        bucket  = aws_s3_bucket.demo.id
}

#Manually created group, attached
data "aws_iam_group" "demo-data" {
        group_name = "Demo-group"
}

resource "aws_s3_bucket_policy" "demo-policy" {
        bucket = aws_s3_bucket.demo.id
        policy = <<EOF
        {
            "Version": "2012-10-17",
            "Statement": [
                {
                    "Action": "*",
                    "Effect": "Allow",
                    "Resource": "arn:aws:s3:::${aws_s3_bucket.demo.id}/*",
                    "Principal": {
                        "AWS": [
                            "${data.aws_iam_group.demo-data.arn}"
                        ]
                    }
                }
            ]
        }
        EOF
}

output of my code is

putting S3 Bucket (demo-2441139) Policy: operation error S3: PutBucketPolicy, https response error StatusCode: 400, RequestID: RXK32HRGG49G5839, HostID: leRuLnPxFnpwCwCIIsQgaqxCi2/RgXkmnnnREXSyWaA1io6FoK0UxLvnJKSmbKRTSThODZW6LPLKnQ7ck4FzqA==, api error MalformedPolicy: Invalid principal in policy
│
│ with aws_s3_bucket_policy.demo-policy,
│ on 02_create_s3.tf line 18, in resource “aws_s3_bucket_policy” “demo-policy”:
│ 18: resource “aws_s3_bucket_policy” “demo-policy” {