GetItem to DynamoDB

Getting the GetItem response from Postman to DynamoDB with Authrorization was successful.
When I execute the Code (cURL or Nodejs-Request) copied from Generate Code Snippets, I get the following error. Why is this?

{"__type": “”, “message”: “The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details.”}