API CORS problem with Server not found error

bugs
1

I recently got access token for my account to use API, but I got CORS network error , how to solve it?

2

To better understand the CORS issue you’re facing, please include more specific information such as:

  • Manager edition

  • Manager version

  • How you are accessing the API (browser, Postman, frontend app, etc.)

  • Example of the request code or configuration

  • The full error message from console or network log

Without these details, it’s difficult to identify the actual cause of the problem.

3

I am accessing the API from a frontend HTML/JavaScript application running in a browser.

Testing environment:

  • Browser: Firefox
  • Local frontend server: Python HTTP server (http://localhost:8000)
  • Request method: JavaScript fetch()

I also tested opening the API endpoint directly in the browser, but the endpoint could not be reached.

API Configuration

API Endpoint:

https://2a05-d018-86e-6302-4e65-1f8a-a992-c98e.ip.manager.cloud/api2

Authentication method:

Authorization: Bearer <API access token>

Example Request Code

Example JavaScript request:

const response = await fetch(
    "https://2a05-d018-86e-6301-7e76-1b9c-e8e2-94fe.ip.manager.cloud/api2/customers",
    {
        method: "GET",
        headers: {
            "Authorization": "Bearer <API_TOKEN>",
            "Accept": "application/json"
        }
    }
);

const data = await response.json();
console.log(data);

Browser Network Log

The browser sends the following preflight request:

OPTIONS /api2/customers undefined

Host: https://2a05-d018-86e-6302-4e65-1f8a-a992-c98e.ip.manager.cloud

Origin: http://localhost:8000

Access-Control-Request-Method: GET

Access-Control-Request-Headers: authorization

The request fails before the actual API call is made.

Error Message

Firefox displays:

Server Not Found

Firefox can’t connect to the server at
2a05-d018-86e-6302-4e65-1f8a-a992-c98e.ip.manager.cloud.

When the endpoint was reachable, the browser request stopped at the CORS preflight stage.

Additional Information

I tested serving the HTML through a local web server instead of opening it directly as a file. The issue remains.

Could you please confirm:

  1. Whether Manager Cloud API supports browser-based CORS requests.
  2. Whether CORS headers can be enabled for API access.
  3. The correct API endpoint and customer-list API path for this instance.
  4. Whether a backend proxy is required for browser applications.
  5. The correct way to retrieve the customer list using the OpenAPI specification.
4

https://2a05-d018-86e-6302-4e65-1f8a-a992-c98e.ip.manager.cloud/api2

Why not just use the normal domain?

It’s working fine for me.

5

CORS compares the complete origin: protocol, hostname and port. Therefore if these are different origins:

https://example.com
http://example.com

If the application runs at https://example.com, the API must return:

Access-Control-Allow-Origin: https://example.com

Using only example.com, or allowing http://example.com, will not match the HTTPS origin.

6

What did you mean in normal domain?

this card comes from access token settings:

```
Access Token

Name testing
Endpoint https://2a05-d018-86e-6300-1106-5b07-560d-1d18.ip.manager.cloud/api2
Secret ********
```

7

The term normal domain refers to endpoints with the standard format:

Code

https://{subdomain}.manager.io

These domains are official, stable, and accessible externally with valid SSL certificates.

However, Manager sometimes returns endpoints using internal domain/IP when generating access tokens, for example:

Code

https://2a05-d018-86e-6300-1106-5b07-560d-1d18.ip.manager.cloud

This type of address is typically only relevant internally and cannot be accessed properly from outside. It often causes SSL or CORS errors.

Since Manager returns endpoints with internal domains that cannot be accessed externally, I am classifying this as a bug so it will be noticed and addressed by the developers.

8

Thank you it now works well in Postman, but in React app I got error:

CORS Missing Allow Origin

9

It seems like this is due to a CORS setting issue in your application.

This should be easily resolved by an AI coding assistant.