Connection Resets during large s3 Multipart upload

Question

I am using DigitalOcean Spaces along with nodejs to upload large files in parts. I'm uploading the file from a ~400mb stream using the following function:

const { S3 } = require('@aws-sdk/client-s3')
const { Upload } = require('@aws-sdk/lib-storage')

module.exports.uploadFileFromStream = async (fileName, readableStream) => {
  const stream = require('stream')
  var pass = new stream.PassThrough()

  const s3Client = new S3({
    endpoint: process.env.s3_endpoint,
    region: process.env.s3_region,
    credentials: {
      accessKeyId: process.env.s3_akey,
      secretAccessKey: process.env.s3_sakey,
    },
  })

  try {
    const u = new Upload({
      client: s3Client,
      params: {
        Bucket: process.env.s3_bucket,
        Key: fileName,
        Body: pass,
        ACL: 'private',
      },
      queueSize: 4,
      partSize: 1024 * 1024 * 5,
      leavePartsOnError: false,
    })
    readableStream.pipe(pass)
    
    await u.done()
  } catch (err) {
    console.log(err)
  }
}

After uploading about 38-39 parts (~200mb), the upload hangs.

I've tried changing the part size and it still hangs after about 200mb (less or more).

It hangs usually after ~30sec.

Using another method, I saw the connection may be reset. What could be the reason and how could I fix this?