When requests to Step Function fail, Workflow Service performs exponential backoff retries to notify Step Function service. Number of retries = 3 The total duration of all attempts doesn't exceed 10 seconds, the processing must not exceed the message visibility timeout.

Script
var AWS = require('aws-sdk');
var stepfunctions = new AWS.StepFunctions();

exports.handler = function(event, context, callback) {
    var params = {
        stateMachineArn: event.stateMachineArn
    };
    stepfunctions.startExecution(params, function(err, data) {
        if (err) {
            console.log(err);
            if (err.code == 'ThrottlingException') {
                context.fail(err);
            } else {
                callback(err);
            }
        } else {
            console.log(data);
            callback(null, data);
        }
    });
};