Architect Data Action 403 Forbidden on Lambda Invoke - IAM Role Trust Issue?

We’re hitting a wall trying to hit a Lambda function from an Architect Data Action. The setup looks right on the surface, but we keep getting a 403 Forbidden response back.

I’ve checked the Lambda permissions and the role attached to the Lambda execution role has the basic AWSLambdaBasicExecutionRole. I also added a policy to allow the CXone service principal, though I’m not 100% sure if that’s even the right approach for outbound calls from Architect.

Here is the Data Action JSON configuration we are using:

{
 "id": "my-lambda-action",
 "type": "web",
 "url": "https://lambda.us-east-1.amazonaws.com/2015-03-31/functions/arn:aws:lambda:us-east-1:123456789:function:my-handler/invocations",
 "method": "POST",
 "timeout": 5000,
 "headers": {
 "Content-Type": "application/json",
 "X-Amz-Target": "AWSLambda_2015_03_31.Invoke"
 },
 "body": "{\"name\": \"test\"}"
}

The error response from the Data Action is just a generic 403 with no helpful message body. I’ve verified the ARN is correct by copying it directly from the AWS console.

Is there a specific IAM policy statement required on the Lambda’s execution role to allow CXone to invoke it? Or do I need to configure the trust policy on the role instead? I’ve tried adding arn:aws:iam::role/cxone-execution-role to the trust policy but that seems wrong since CXone is external.

Any idea what I’m missing here?