Get Request always results in an error

I just can’t manage to get a proper response on my get requests. Neither from frontend nor backend code! I tried the exact same get request on both sides.

On frontend the error is as follows:
TypeError: NetworkError when attempting to fetch resource.

On backend:
Error: Gateway Timeout

the code:
export function getCall(){
const url = ‘https://a-valid-url-as-stated’';

return fetch(url, {
“method”: ‘get’
.then((httpsResponse) => {

the url itself is not the issue as it works on various Rest clients!
Unfortuantely I can’t share the url as it points to a private API.

Any help is appreciated.