s3 multipart upload - XML provided was not well-formed or did not validate against our public schema

[dMaisnam]

I am working on a Node backend and React frontend where I am using multipart upload strategy to upload larger files. I am currently trying to achieve this with @aws-sdk version 2 and plan to upgrade once I solve this issue. The error I got was a 400 MalformedXML error that reads The XML you provided was not well-formed or did not validate against our published schema

The process goes like this

1. Get an uploadId from the backend
2. Split the file into smaller chunks and then get a pre-signed URL for each chunk/part
3. Using the obtained pre-signed URL, PUT the file using the obtained url
4. Arrange all the parts in an array into objects containing the part number and etag to complete the upload

The whole request process, the frontend and backend codes are referenced here in this snippet
https://stackblitz.com/edit/web-platform-9ofkbt

The bucket policy

{
   "Version": "2008-10-17",
   "Statement": [
       {
           "Sid": "AllowPublicRead",
           "Effect": "Allow",
           "Principal": {
               "AWS": "*"
           },
           "Action": "s3:GetObject",
           "Resource": "arn:aws:s3:::my-test-bucket/*"
       }
   ]
}

Bucket CORS config

[
   {
       "AllowedHeaders": [
           "*"
       ],
       "AllowedMethods": [
           "PUT",
           "HEAD",
           "GET"
       ],
       "AllowedOrigins": [
           "*"
       ],
       "ExposeHeaders": [
           "x-amz-server-side-encryption",
           "x-amz-request-id",
           "x-amz-id-2",
           "ETag"
       ],
       "MaxAgeSeconds": 3000
   }
]

What am I doing wrong here? I have been stuck with this problem for a few days now and am out of ideas as to how to tackle this.
Can anyone help me with this issue? Any help is much appreciated. Thanks for reading.

[dMaisnam]

My bad. Turns out I was using the wrong variable name from the request body. I should be using req.body.parts instead of req.body.partNumber which I was using in my controller file (not included in the Stackblitz code snippet).

[github-actions[bot]]

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