Facing CORS error on AWS ECS Fargate container

Question

I have deployed my application backend on AWS ECS Fargate container and I deployed my application on second AWS ECS Fargate container. Both, frontend and backend, are using two different load balancers. But when I try to connect my frontend with backend it is throwing a CORS error that you can see in the following picture.

CORS ERROR

Does anyone have any idea why this error is coming and how I can resolve it?

![CORS ERROR](/media/postImages/original/IMtioicrX8ThG8QtwRu35mEQ)

Does anyone have any idea why this error is coming and how I can resolve it?

Accepted Answer

CORS (Cross Origin Resource Sharing) is a browser policy-related(Same Origin Policy) error that occurs when referring to resources from other sources (domain, port). The workaround for this is to have a proxy server, or to have the following settings in the backend application:

This is(below) just example and depends on the language/framework you use.

```
res.setHeader('Access-Control-Allow-Origin', "{Client Domain}");
res.header('Access-Control-Allow-Methods', 'GET, OPTIONS, PUT, POST');
res.header('Access-Control-Allow-Headers', 'Content-Type, Authorization');
res.header('Access-Control-Allow-Credentials', 'true');
```

Facing CORS error on AWS ECS Fargate container

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