Data Action Lambda call returning 403 Forbidden

Architect & Flows
1

Trying to hit an AWS Lambda from a Genesys Architect Data Action but keep getting a 403 Forbidden. The role has the InvokeFunction policy attached. Here’s the JSON config I’m using:

{
 "url": "https://lambda.us-east-1.amazonaws.com/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789:function:myFunc/invocations",
 "method": "POST",
 "headers": {
 "Content-Type": "application/json"
 }
}

Any idea why the signature validation is failing?