I have a question about Fetch() API.

In order to display JSON data from addresses with different domains in the ReactJS page component in the console window, I wrote the code as below.

const url = 'http://example.com/';

fetch(
    url, {
        'Accept': 'application/json',
        'Content-Type': 'application/json',
        'Auth-Key': 'Lrmgdf...'
    },
    method: 'POST'
).then(
    response => response.json()
).then(
    data => console.log(data));

Chrome encountered a CORS error, but I thought it wouldn't matter if it was called on another domain, but Chrome actually shows the following error log.

Unhandled Rejection (TypeError): Failed to execute 'fetch' on 'Window': Invalid name

The caller is written in PHP and can only be accessed with Auth-Key, so I asked you this question because I couldn't find the right keyword even if I googled.

I would appreciate it if you could just tell me the API or method related to it.