title: DynamoDB: What might be the reason for TransactionInProgressException
body: <p>Using transactWriteItems from the aws-sdk(js) document client we get a TransactionInProgressException with the message: "Transaction from previous request is still in progress".
  From the documentation for <a href="https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_TransactWriteItems.html" rel="nofollow noreferrer">TransactWriteItem</a>it only states:</p>
  
  <blockquote>
    <p>The transaction with the given request token is already in progress.</p>
  </blockquote>
  
  <p>As far as I understand it the request token is unique for each TransactWriteItem, which is taken care of by document client. So given the fact this transaction was triggered once from the application what would be the root cause for this error?</p>