Synthetics Canary keeps failing with 403 error

I cannot get canary to hit api gateway endpoint. I keep getting an error below. I can hit the api using postman without authentication key so not sure why I can't do the same using synthetic canary. The API is within the same account as the canary also if this helps. Please can anyone help me with this? (Arn changed for privacy so please ignore this fact.)

{"message":"User: anonymous is not authorized to perform: execute-api:Invoke on resource: arn:aws:execute-api:us-east-1:********2234:54354534534/test/GET/mezzanine with an explicit deny"}

The code I have for the canary is:

const synthetics = require('Synthetics'); const log = require('SyntheticsLogger'); const syntheticsConfiguration = synthetics.getConfiguration();

const apiCanaryBlueprint = async function () {

syntheticsConfiguration.setConfig({
    restrictedHeaders: [], // Value of these headers will be redacted from logs and reports
    restrictedUrlParameters: [] // Values of these url parameters will be redacted from logs and reports
});

// Handle validation for positive scenario
const validateSuccessful = async function(res) {
    return new Promise((resolve, reject) => {
        if (res.statusCode < 200 || res.statusCode > 299) {
            throw new Error(res.statusCode + ' ' + res.statusMessage);
        }

        let responseBody = '';
        res.on('data', (d) => {
            responseBody += d;
        });

        res.on('end', () => {
            // Add validation on 'responseBody' here if required.
            resolve();
        });
    });
};


// Set request option for Verify https://453453453.execute-api.us-east-1.amazonaws.com
let requestOptionsStep1 = {
    hostname: '4534535.execute-api.us-east-1.amazonaws.com',
    method: 'GET',
    path: '/test/mezzanine',
    port: '443',
    protocol: 'https:',
    body: "",
    headers: {"health":"true"}
};
requestOptionsStep1['headers']['User-Agent'] = [synthetics.getCanaryUserAgentString(), requestOptionsStep1['headers']['User-Agent']].join(' ');

// Set step config option for Verify https://5345345345435.execute-api.us-east-1.amazonaws.com

let stepConfig1 = { includeRequestHeaders: true, includeResponseHeaders: true, includeRequestBody: true, includeResponseBody: true, continueOnHttpStepFailure: true };

await synthetics.executeHttpStep('Verify https://45345334535.execute-api.us-east-1.amazonaws.com', requestOptionsStep1, validateSuccessful, stepConfig1);

};

exports.handler = async () => { return await apiCanaryBlueprint(); };

For the API I have no Auth on and the resource Policy is:

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": "", "Action": "execute-api:Invoke", "Resource": "arn:aws:execute-api:us-east-1:34324234234234:343243242///" }, { "Effect": "Deny", "Principal": "", "Action": "execute-api:Invoke", "Resource": "arn:aws:execute-api:us-east-1:3432434234:434324234///", "Condition": { "NotIpAddress": { "aws:SourceIp": [ "23.23.23.23/32", "23.23.23.23/32", "23.23.23.23/32" ] } } } ] }

I have also tried leaving the resource policy blank and also with the below code but still cannot get this canary to work.

{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": "", "Action": "execute-api:Invoke", "Resource": "arn:aws:execute-api:us-east-1:4534534543:4543534543534///" } ] }