Error with Severless Function using Lambda AWS

I followed the below link to do a similar setup with S3 static website + AWS API Gateway + AWS Lambda.

https://aws.amazon.com/blogs/architecture/create-dynamic-contact-forms-for-s3-static-websites-using-aws-lambda-amazon-api-gateway-and-amazon-ses/

I am getting 405 Method not allowed when I hit the submit button on the s3 form. I know S3 static web hosting doesn't allow POST. Is there a workaround for this?