I have this code in my express server that generates an S3 presigned url using NodeJS AWS SDK:

const { S3Client } = require("@aws-sdk/client-s3");
const { getSignedUrl } = require("@aws-sdk/s3-request-presigner");
    
app.get('/getS3PresignedUrl', async (req, res) => {


  const s3 = new S3Client({
      region: 'ap-southeast-2',
      credentials: {
        accessKeyId: accessKey.data.access_key,
        secretAccessKey: accessKey.data.secret_key
      }

    });
  const presignedS3Url = await getSignedUrl(s3, new PutObjectCommand({
      Bucket: 'xxx',
      Key: 'test.txt',
    }) 
  );
  res.send({
    status: true,
    message: 'success',
    data: {
      s3Url: presignedS3Url 
    }
  });
})

Once I get the URL, I use that and put it in either curl or Postman but both gets 403 InvalidAccessKeyId. For example:

1. curl
2. Postman

I don't understand why it fails with 403 when the S3 url is generated successfully? Note, I use that url right away and does not exceed the 900 seconds expire limit.

Any ideas what is the issue here?