I want a certain HTTPS service to be called every time a file has been uploaded to an S3 bucket.

I have created the S3 bucket and a SNS topic with a verified subscription with the HTTPS service as an endpoint. I can publish a message on the SNS topic via the AWS UI, and see that the HTTPS service is called as expected. On the S3 bucket I created an Event, which should link the bucket and the topic. On my first attempt I got an error because the bucket was not allowed to write to the topic, so c.f. the documentation, I changed the topic access policy to:

{
  "Version": "2008-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": "*",
      "Action": "sns:Publish",
      "Resource": "arn:aws:sns:eu-central-1:TOPIC_ID:OrderUpdates",
      "Condition": {
        "StringEquals": {
          "AWS:SourceAccount": "ACCOUNT_ID"
        },
        "ArnLike": {
          "AWS:SourceArn": "arn:aws:s3:*:*:*"
        }
      }
    }
  ]
}

where TOPIC_ID is the topic owner id which can be seen when the topic is shown in the AWS UI, and the ACCOUNT_ID is the account id shown under account settings in the AWS UI. This change in the topic access policy allowed me to create the event on the bucket:

When I call the API method getBucketNotificationConfiguration I get:

{
    "TopicConfigurations": [
        {
            "Id": "OrderFulfilled",
            "TopicArn": "arn:aws:sns:eu-central-1:TOPIC_ID:OrderUpdates",
            "Events": [
                "s3:ObjectCreated:*"
            ]
        }
    ],
    "QueueConfigurations": [],
    "LambdaFunctionConfigurations": []
}

But the HTTPS service is not called. What am I missing in this setup, that will trigger the HTTPS service to be called by the SNS topic subscription every time a file is uploaded to the S3 bucket?

Thanks, -Louise