将请求从S3静态网站路由到EC2实例

I have a problem that I cant POST/GET from my website to my backend API. Front-end which is implemented with angular 5 is held in Amazon S3 bucket as a static website. How can you make your angular 5 front-end interact with API that is hosted in EC2 instance? Both applications are working but not interacting to change information. So how can you POST/GET data from Amazon S3 to EC2 instance based backend?I have a problem that I cant POST/GET from my w