Inaccessible host: `freetier.us-east-1.amazonaws.com' at port `undefined'. This service may not be available in the `us-east-1' region

I'm trying to call AWS Free Tier API from a Lambda function, but I'm getting this error:

Inaccessible host: `freetier.us-east-1.amazonaws.com' at port `undefined'. This service may not be available in the `us-east-1' region.

Free tier API documentation:

https://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/FreeTier.html

My code:

const AWS = require('aws-sdk');

module.exports = {
    getFreeTierUsage: async (awsCredential) => {
        var freetier = new AWS.FreeTier({
            accessKeyId: awsCredential.accessKeyId,
            secretAccessKey: awsCredential.secretAccessKey
        });
        var params = {};
        let result = await freetier.getFreeTierUsage(params).promise();
        return result;
    }
}

What's wrong?

It looks like AWS is changing the URL format for their APIs.

Traditionally it would look something like:

https://freetier.us-east-1.amazonaws.com

However, the Class: AWS.FreeTier — AWS SDK for JavaScript documentation is showing it as:

https://freetier.us-east-1.api.aws

Need to include the endpoint parameter like this:

    var freetier = new AWS.FreeTier({
        endpoint: 'https://freetier.us-east-1.api.aws',
        accessKeyId: awsCredential.accessKeyId,
        secretAccessKey: awsCredential.secretAccessKey
    });