title: {"message":"The security token included in the request is invalid."}
body: <p>I'm using serverless Now for a tool invoking AWS via Slack API. The script works fine locally and on server, but I'm having issues in making it work using Now Platform.</p>
  
  <p>This is the error I'm getting:</p>
  
  <pre><code>{"message":"The security token included in the request is invalid."}
  </code></pre>
  
  <p>There are several questions regarding this, but they don't seem to answer my problem as I see the AWS credentials are correctly configured running <code>cat ~/.aws/credentials</code>.</p>
  
  <p>I am using <a href="https://github.com/DavidMuller/aws-requests-auth" rel="nofollow noreferrer">AWS Requests Auth</a>:</p>
  
  <pre><code>auth = AWSRequestsAuth(aws_access_key=os.environ['AWS_ACCESS_KEY_ID'],
                                     aws_secret_access_key=os.environ['AWS_SECRET_ACCESS_KEY'],
                                     aws_host='restapiid.execute-api.us-east-1.amazonaws.com',
                                     aws_region='us-east-1',
                                     aws_service='execute-api')
  
  headers = {"Content-Type":"application/json"}
  response = requests.post('https://restapiid.execute-api.us-east-1.amazonaws.com/path', auth=auth, headers=headers, data=payload)
  </code></pre>
  
  <p>As the error is usually 403, I suspect is a <code>Signature expired</code> issue, but I don't know how to sync Now timestamp with AWS one.</p>